What is the smallest whole number that is equal to seven times the sum of its digits? -Riddles

What is the smallest whole number that is equal to seven times the sum of its digits? -Riddles
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The answer to this math riddle is 21. You probably just guessed to answer this math riddle, which is fine, but you can also work it out algebraically. The two-digit number ab stands for 10a + b since the first digit represents 10s and the second represents units. If 10a + b = 7(a + b), then 10a + b = 7a + 7b, and so 3a = 6b, or, more simply, a = 2b. That is, the second digit must be twice the first. The smallest such number is 21.
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Related questions

A certain number has three digits. The sum of the three digits equals 36 times this number. Seven times the left digit plus 9 is equal to 5 times the sum of the two other digits. 8 times the second digit minus 9 is equal to the sum of the first and third.What is the number? -Riddles

Description : A certain number has three digits. The sum of the three digits equals 36 times this number. Seven times the left digit plus 9 is equal to 5 times the sum of the two other digits. 8 times the second digit minus 9 is equal to the sum of the first and third.What is the number? -Riddles

Last Answer : This one is fairly easy - 324 is the answer.

I am a five-digit whole number, read the same forward, backward and upside down. My second digit is half my third digit; my fifth digit is the product of my first and last digits; and the sum of my whole is ten. What am I? -Riddles

Description : I am a five-digit whole number, read the same forward, backward and upside down. My second digit is half my third digit; my fifth digit is the product of my first and last digits; and the sum of my whole is ten. What am I? -Riddles

Last Answer : 10801

What four digit positive, whole number has its last and first digits equal, addition of its last two digits is equal to its second digit. And the product of the squares of its last two digits is equal to four two noughts. -Riddles

Description : What four digit positive, whole number has its last and first digits equal, addition of its last two digits is equal to its second digit. And the product of the squares of its last two digits is equal to four two noughts. -Riddles

Last Answer : 5945. 5=5. 4+5=9=second digit 4^2 x 5^2 = 400 = four two noughts

(A) Use two digits to make the smallest possible positve intiger.(B) Five 3s can express 37: 37=33+3+3/3Find another way to do it.(C) Use six identical dgits to make 100. (Several solutions are possible.)(D) Use five 4s to make 55.(E) Use four 9s to make 20. -Riddles

Description : (A) Use two digits to make the smallest possible positve intiger.(B) Five 3s can express 37: 37=33+3+3/3Find another way to do it.(C) Use six identical dgits to make 100. (Several solutions are possible.)(D) Use five 4s to make 55.(E) Use four 9s to make 20. -Riddles

Last Answer : (A) 1 X 1; 1/1;2/2;ect....;1-0;2-1;and many others. (B) 37=333/3X3; 37=3 X 3 X 3 + 3/.3 (C) 99 + 99/99; 55+55- 5- 5; (666-66)/6 (D) 44 + 44/4=55. (E) 9 + 99/9=20.

If a whole number between 100 and 999 has 3 different non zero digits What is the least possible value of the sum of its digits?

Description : If a whole number between 100 and 999 has 3 different non zero digits What is the least possible value of the sum of its digits?

Last Answer : 6

When the celebrated German mathematician Karl Friedrich Gauss (1777-1855) was nine he was asked to add all the integers from 1 through 100. He quickly added 1 to 100, 2 to 99, and so on for 50 pairs of numbers each adding to 101. 50 X 101=5,050.Now find the sum of all the digits in integers from 1 through 1,000,000,000.That's all the digits in all the numbers, not all the numbers themselves. -Riddles

Description : When the celebrated German mathematician Karl Friedrich Gauss (1777-1855) was nine he was asked to add all the integers from 1 through 100. He quickly added 1 to 100, 2 to 99, and so on for 50 pairs ... 1,000,000,000.That's all the digits in all the numbers, not all the numbers themselves. -Riddles

Last Answer : The numbers can be grouped by pairs: 999,999,999 and 0; 999,999,998 and 1' 999,999,997 and 2; and so on.... There are half a billion pairs, and the sum of the digits in each pair is 81. The digits in the unpaired number, 1,000,000,000, add to 1. Then: (500,000,000 X 81) + 1= 40,500,000,001.

The square of a two digit number is divided by half the number. After 36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in the original number, but they are in reverse order. The ten's place of the original number is equal to twice the difference between its digits. What is the number?

Description : The square of a two digit number is divided by half the number. After 36 is added to the quotient, this sum is then divided by 2. The digits of the resulting number are the same as those in ... 's place of the original number is equal to twice the difference between its digits. What is the number?

Last Answer : Answer: 46

In an examination mahi scores 64% of marks, nitesh scores 52% of marks and ritesh scores 48% of marks. The maximum mark of the exam is a three digit number, whose sum is 10 and the middle digit is equal to the sum of the other two digits. The number will decreased by 297, if its digit are reversed. approximately what is the average mark obtained by mahi, nitesh and ritesh? A) 247 B) 248 C) 264 D) 284

Description : In an examination mahi scores 64% of marks, nitesh scores 52% of marks and ritesh scores 48% of marks. The maximum mark of the exam is a three digit number, whose sum is 10 and the middle digit is equal to ... what is the average mark obtained by mahi, nitesh and ritesh? A) 247 B) 248 C) 264 D) 284

Last Answer : A) Maximum mark consist of a three digit number let's consider Unit digit place is Z,ten's place digit is Y and hundred's place digit is X. According to the question, Y=x+z---------1 X+Y ... Total number of Mahi, Nitesh and Ritesh =164/100 451=739.61 Required average =739.64/3=246.54~247.

A number say z is exactly the four times the sum of its digits and twice the product of the digits. Find the numbers -Maths 10th

Description : A number say z is exactly the four times the sum of its digits and twice the product of the digits. Find the numbers -Maths 10th

Last Answer : This is the Answer

What two-digit number equals two times the result of multiplying its digits? -Riddles

Description : What two-digit number equals two times the result of multiplying its digits? -Riddles

Last Answer : 36 = 2 x 3 x 6.

I am a seven lettered word; my first three letters refer to a place a driver sits in a bus. My first five letters refer to a small room on a ship; my middle three letters is a container people put waste in. My last three letters refer to one which catches fish. My whole refer to a furniture with doors. What am I? -Riddles

Description : I am a seven lettered word; my first three letters refer to a place a driver sits in a bus. My first five letters refer to a small room on a ship; my middle three letters is a container people ... letters refer to one which catches fish. My whole refer to a furniture with doors. What am I? -Riddles

Last Answer : A Cabinet.

In the same way you can make four fives in an equation to equal 100, (5+5)X(5+5)=100, can you make an equation with only four sevens and no other digits to make 100? -Riddles

Description : In the same way you can make four fives in an equation to equal 100, (5+5)X(5+5)=100, can you make an equation with only four sevens and no other digits to make 100? -Riddles

Last Answer : (7/.7)X(7/.7)=100 As 7/.7 = 10 The equation becames equivalent to 10X10

0,1,2,3,4,5,6,7,8,9 Use the digits above once each only to compose two fractions which when added togeather equal 1. -Riddles

Description : 0,1,2,3,4,5,6,7,8,9 Use the digits above once each only to compose two fractions which when added togeather equal 1. -Riddles

Last Answer : 35/70 + 148/296 = 1

Write the given sets in roster form: (a). P = {y: y is an integer and -4 < y < 6}. (b). Q = {y: y is a natural number which is <8} (c). R = {y: y is a 2 digit natural number in which the sum of its digits is 9} -Other

Description : Write the given sets in roster form: (a). P = {y: y is an integer and -4 < y < 6}. (b). Q = {y: y is a natural number which is

Last Answer : (i) A = {x: x is an integer and †3 < x < 7} The elements of this set are †2, †1, 0, 1, 2, 3, 4, 5, and 6 only. Therefore, the given set can be written in roster form as A = {†2, †... and 80 only. Therefore, this set can be written in roster form as C = {17, 26, 35, 44, 53, 62, 71, 80}}.

When 10 to the 507th power - 2 written as a natural number the sum of its digits is?

Description : When 10 to the 507th power - 2 written as a natural number the sum of its digits is?

Last Answer : It is 4562.

What are the numbers in the smallest group of repeating digits when 4111 is converted to a nonterminating decimal?

Description : What are the numbers in the smallest group of repeating digits when 4111 is converted to a nonterminating decimal?

Last Answer : 4111 is an integer and so there is no sensible way to convert itinto a repeating decimal.

How can you divide seven apple into two equal parts and still have five each? -Riddles

Description : How can you divide seven apple into two equal parts and still have five each? -Riddles

Last Answer : It's to separate the phrase, 'seven apple' into two: 'seven' and 'apple', each having five letters! Got it?

I am a two-digit number. All my digits are even. No two digits are the same. None of my digits are prime numbers. I am not a multiple of ten. My tens digit is bigger than my other numbers. If you followed all the previous steps, there should be three options remaining the number is the option where if you add all the digits it’s exactly in the middle (in how big the number is) of all the other options with their digits added together. What number am I? -Riddles

Description : I am a two-digit number. All my digits are even. No two digits are the same. None of my digits are prime numbers. I am not a multiple of ten. My tens digit is bigger than my other numbers. ... big the number is) of all the other options with their digits added together. What number am I? -Riddles

Last Answer : If you followed all the steps apart from the last one there will be three options remaining: 64, 84, and 86. You then had to add up the digits, 64=6+4=10, 84=8+4=12, and 86=8+6=14. ... biggest number (12) and put it back as it was before the digits were added together and your answer should be 84.

This number added to it's square, and the digits of that summation added together, bring it back to itself. What is it? -Riddles

Description : This number added to it's square, and the digits of that summation added together, bring it back to itself. What is it? -Riddles

Last Answer : 3. 3 squared is 9. 3+9=12. Take the two digits of the summation and add them; 1+2=3. In short; 3-9-12-3. This can also work with the number 0 and 9.

In a two-digit number, the sum of the digits is 9. If 9 is subtracted from the number, then the digits get reversed. Find the product of the digits

Description : In a two-digit number, the sum of the digits is 9. If 9 is subtracted from the number, then the digits get reversed. Find the product of the digits

Last Answer : In a two-digit number, the sum of the digits is 9. If 9 is subtracted from the number, then the digits get reversed. Find the product of the digits

In a two-digit number, the sum of the digit is 5 more than the units digit. The difference between the original number and the sum of digits is 10 mor

Description : In a two-digit number, the sum of the digit is 5 more than the units digit. The difference between the original number and the sum of digits is 10 mor

Last Answer : In a two-digit number, the sum of the digit is 5 more than the units digit. The ... the digits. Then find the difference between the digits.

In a two-digit number, the ten digit is one more than twice the units digit. The sum of the digits is 36 less than the number formed by reversing the

Description : In a two-digit number, the ten digit is one more than twice the units digit. The sum of the digits is 36 less than the number formed by reversing the

Last Answer : In a two-digit number, the ten digit is one more than twice the units digit. The sum of ... by reversing the digits. Find the product of the digits

What is a two digit number whose sum of those digits is the square root of that number?

Description : What is a two digit number whose sum of those digits is the square root of that number?

Last Answer : The number is 81.

A two digit number is such that the sum of the digits is 11.When the number with the same digits is reversed is subtracted from this number, the difference is 9.What is the number? 1. 23 2. 24 3. 65 4. 14 5. 32

Description : A two digit number is such that the sum of the digits is 11.When the number with the same digits is reversed is  subtracted from this number, the difference is 9.What is the number? 1. 23 2. 24 3. 65 4. 14 5. 32

Last Answer : Answer- 3(65) Explanation:- let the number be written as xy x-ten’s place y units place x+y=11…………………1 (10x+y)-(10y+x)=9 10x+y-10y-x=9 9x-9y=9 x-y=1………………….2 Add (1) & (2) 2x=12 x=6 y=5 the number is 65

A number consists of two digits whose sum is 8. If 8 is subtracted from the number, the digits interchange their places. The number is (1) 44 (2) 35 (3) 62 (4) 33

Description : A number consists of two digits whose sum is 8. If 8 is subtracted from the number, the digits interchange their places. The number is (1) 44 (2) 35 (3) 62 (4) 33

Last Answer : (4) 33

I am a three-digit number. All of my digits are prime. One of the numbers is even. Each of my numbers are used only once. The total of my first and last digits equals 10. The total of my first two digits equals 5. -Riddles

Description : I am a three-digit number. All of my digits are prime. One of the numbers is even. Each of my numbers are used only once. The total of my first and last digits equals 10. The total of my first two digits equals 5. -Riddles

Last Answer : This one is fairly easy if you use elimination if you follow all the first 5 steps you get three options: 525, 327, and 723 but if you followed the last step you would reach your answer. The answer was 327.

I have 3 digits. The tens place is 3 more than the ones place the hundrends place is 2 more than the tens place. What number am I? -Riddles

Description : I have 3 digits. The tens place is 3 more than the ones place the hundrends place is 2 more than the tens place. What number am I? -Riddles

Last Answer : 863!

What is the highest number that can be written with three digits? -Riddles

Description : What is the highest number that can be written with three digits? -Riddles

Last Answer : (9⁹)⁹ = 9³⁸⁷⁴²⁰⁴⁸⁹, which is a number with more than 369 million digits.

What is the 4 digit number in which the first digit is one-fifth of the last, and the second and third digits are the last digit multiplied by 3? -Riddles

Description : What is the 4 digit number in which the first digit is one-fifth of the last, and the second and third digits are the last digit multiplied by 3? -Riddles

Last Answer : 1155

The method which depreciates the tractor or machine to zero at the end of its expected life is known as: A. Estimated value B. Sum-of-the digits C. Declining balance D. Straight line

Description : The method which depreciates the tractor or machine to zero at the end of its expected life is known as: A. Estimated value B. Sum-of-the digits C. Declining balance D. Straight line

Last Answer : D. Straight line

Find sum of digits -Maths 9th

Description : Find sum of digits -Maths 9th

Last Answer : answer:

Suresh and Ramesh are twins. In a form by mistake, Suresh reverses the last 2 digits of his year of birth, and this makes him 9 years older than Ramesh. With this mistake, the sum of their ages in 2015 becomes 43. How old will Ramesh be 2021? a) 17 b) 19 c) 21 d) 23 e) 25

Description : Suresh and Ramesh are twins. In a form by mistake, Suresh reverses the last 2 digits of his year of birth, and this makes him 9 years older than Ramesh. With this mistake, the sum of their ages in 2015 becomes 43. How old will Ramesh be 2021? a) 17 b) 19 c) 21 d) 23 e) 25

Last Answer : Let the correct ages of Ramesh and Suresh be X in 2015 (since they are twins, they will have the same age) Given: 2x + 9 = 43 Or x = 17 years in 2015. Age in 2021 = 17 + 6 = 23 Note: year of birth = 2015 – 17 = 1998. Reversing, Suresh = 1989 or 9 year older. Answer: d)

How many strings of 5 digits have the property that the sum of their digits is 7 ? (A) 66 (B) 330 (C) 495 (D) 99

Description : How many strings of 5 digits have the property that the sum of their digits is 7 ? (A) 66 (B) 330 (C) 495 (D) 99

Last Answer : (B) 330

I have four digits, I own a lot of cash money money, I'm kept a secret, but used on the daily. What am I? -Riddles

Description : I have four digits, I own a lot of cash money money, I'm kept a secret, but used on the daily. What am I? -Riddles

Last Answer : Pin number.

The combined age of a father and daughter is 66. The daughter is the same age as the father. But with the digits reversed. What are their ages? -Riddles

Description : The combined age of a father and daughter is 66. The daughter is the same age as the father. But with the digits reversed. What are their ages? -Riddles

Last Answer : There are three correct answers 51 and 15, 42 and 24, or 60 and 6.

How many pluses should we put between the digits of 987,654,321 to get a total of 99, and where? -Riddles

Description : How many pluses should we put between the digits of 987,654,321 to get a total of 99, and where? -Riddles

Last Answer : (6) 9 + 8 + 7 + 6 + 5 + 43 + 21= 99 (7) 9 + 8 + 7 + 65 + 4 + 3 + 2 + 1= 99

A student was once given a simple task to accomplish. He was given 6 numbers: 1, 10, 20, 30, 40, and 80, and was told to sum them together to be equal to 100. At last, he was able to accomplish this task. How did he do it? -Riddles

Description : A student was once given a simple task to accomplish. He was given 6 numbers: 1, 10, 20, 30, 40, and 80, and was told to sum them together to be equal to 100. At last, he was able to accomplish this task. How did he do it? -Riddles

Last Answer : He read 10 and 80 backwards to give him 01 and 08 respectively. So, 1 + 01 + 20 + 30 + 40 + 08 = 100.

A man has nine children, born at regular intervals. The sum of their squares of their ages is equal to the square of his own age.What are the ages of the children? -Riddles

Description : A man has nine children, born at regular intervals. The sum of their squares of their ages is equal to the square of his own age.What are the ages of the children? -Riddles

Last Answer : 2 - 5 - 8 - 11 - 14 - 17 - 20 - 23 - 26

You have seven pens and nine pigs. You must arrange the pens so that each pen has an even number of pigs. Zero is not allowed, nor will it work. How do you do this? -Riddles

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Last Answer : Stack the pens.

I have 10 books and I label them with their number. I take seven out to read. How many books are left? -Riddles

Description : I have 10 books and I label them with their number. I take seven out to read. How many books are left? -Riddles

Last Answer : 9! You have token the book with the label seven!

Zero sum game has player… a. seven b. Two c.three player d. Multiplayer

Description : Zero sum game has player… a. seven b. Two c.three player d. Multiplayer

Last Answer : d. Multiplayer

The sum of three consectuve integers is 24. Find the smallest number

Description : The sum of three consectuve integers is 24. Find the smallest number

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The total power consumed in a parallel circuit is __________. A. the sum of the powers used in each load (resistor) divided by the number of loads B. always less than the power used in the smallest load C. the sum of the powers used in each individual load D. never more than the power used in the largest load

Description : The total power consumed in a parallel circuit is __________. A. the sum of the powers used in each load (resistor) divided by the number of loads B. always less than the power used in the smallest ... of the powers used in each individual load D. never more than the power used in the largest load

Last Answer : Answer: C

The total power used up in a series circuit is ___________. A. the sum of the powers used in each load (resistor) divided by the number of loads B. the sum of the powers used in each load C. always less than the power used in the smallest load D. never more than the power used in largest load

Description : The total power used up in a series circuit is ___________. A. the sum of the powers used in each load (resistor) divided by the number of loads B. the sum of the powers used in each load C. always less than the power used in the smallest load D. never more than the power used in largest load

Last Answer : Answer: B

The least count of a Vernier scale is (A) Sum of the smallest divisions of main and Vernier scales (B) Value of one division of the primary scale divided by total number of divisions of Vernier scale (C) Value of one division of Vernier scale divided by total number of divisions of primary scale (D) None of these

Description : The least count of a Vernier scale is  (A) Sum of the smallest divisions of main and Vernier scales  (B) Value of one division of the primary scale divided by total number of divisions ... division of Vernier scale divided by total number of divisions of primary scale  (D) None of these 

Last Answer : (B) Value of one division of the primary scale divided by total number of divisions of Vernier  scale 

Find the smallest number in a GP whose sum is 38 and product 1728? (a) 12 (b) 20 (c) 8 (d) none of these

Description : Find the smallest number in a GP whose sum is 38 and product 1728? (a) 12 (b) 20 (c) 8 (d) none of these

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What number is a 3 digit square number with the product of its digits equal to 2?

Description : What number is a 3 digit square number with the product of its digits equal to 2?

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What has seven holes in it and is shaped like a ball? Hint: It is a body part. -Riddles

Description : What has seven holes in it and is shaped like a ball? Hint: It is a body part. -Riddles

Last Answer : Your head.