The average age of students of a college is 31.6 yrs. The average age of boys in the class is 32.8 yrs and that of girls is 30.8. The ratio of number of boys to the number of girls in the class. A) 2:3 B) 3:1 C) 1:3 D) 3:2

The average age of students of a college is 31.6 yrs. The average age of boys in the class is 32.8 yrs and that of girls is 30.8. The ratio of number of boys to the number of girls in the class. A) 2:3 B) 3:1 C) 1:3 D) 3:2
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1 Answer

Answer :

A)

Let the ratio be D:1.then,

(D * 32.8) + ( 1* 30.8)= (D+1) * 31.6

32.8 D +30.8 = 31.6 D + 31.6

32.8 D – 31.6D = 31.6 – 30.8

1.2D = 0.8

D = 0.8/1/2 = 0.4/0.6

D = 2/3

Required ratio = 2/3 :1 = 2:3.
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Related questions

The average age of 160 boys in a class is 58 yrs. The average group of 30 boys in the class is 42 yrs and the average of another group of 50 boys in the class is 36 years. What is the average age of the remaining boys? A) 72.58 B) 74.25 C) 77.75 D) 75.68

Description : The average age of 160 boys in a class is 58 yrs. The average group of 30 boys in the class is 42 yrs and the average of another group of 50 boys in the class is 36 years. What is the average age of the remaining boys? A) 72.58 B) 74.25 C) 77.75 D) 75.68 

Last Answer : C) Total age of 160 boys = 160* 58= 9280 total age of 30 boys = 30 * 42= 1260 total age of next 50boys = 50 * 36= 1800 average of the remaining boys = [(9280-{1260+1800})/[160 - (30 + 50)] =>9280-3060/80 =>6220/80 =77.75yrs

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Last Answer : Answer: A)  Let initial expense of 32 boys = Rs. x average expense of 32 boys = x/32 average expense of 47 boys = (x + 43)/ 47 then, (x/32) - ((x+43)/47) = 2  x= Rs.108.28

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The average age of the men in a team is 76 years and that of the women is 75 years. The average age for the whole team is. A) 75 yrs B) 75.5 yrs C) Cannot be computed with the given information D) None of the above

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Average age of A, B, C is 90yrs, however when D joins them, then the average comes down to 80 yrs. Now a new person E, whose age is six-fifth of the age of D, replaces A and the new average is 78. What is age of A? A) 64 B) 68 C) 62 D) 66

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The average age of three -seventh of class is 49, what should be the average of remaining four-seventh students so that the average of the entire class is 63? A) 24.5 B) 86.5 C) 73.5 D) 25.5

Description : The average age of three -seventh of class is 49, what should be the average of remaining four-seventh students so that the average of the entire class is 63? A) 24.5 B) 86.5 C) 73.5 D) 25.5

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The average monthly salary of directors & office boys of an organization Rs. 3750. Then the average salary of all directors is Rs. 6000 while that of all office boys is Rs. 3000 per month. If there are 120 employees in the organization then find the ratio of manager and office boy. A) 2:5 B) 3:1 C) 1:3 D) 5:2

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Students of two colleges appeared for Talent test carrying 250marks as maximum. The average of their marks for college1 & college 2 are 160 & 180respectively. If the number of students of college 1 is the half of the number of students of college 2, then what is the average marks of all students of both the college? A) 170 B) 110 C) 173.33 D) 177.33

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Gowshik is going to market from his home by bike at a speed of 20kmph. While he comes back to his home with a speed of X kmph, what should be the value of x so that his average speed is 24kmph ? A) 24 B) 34 C) 30 D) 32

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on analyzing the result of an competitive exam the teacher found that the average for the entire the class was 69 marks. If we say that average of 10 % of the students scored 77 marks and average of 28 % of the students scored 66 marks, then calculate average marks of the remaining students of the class A) 67.54 B) 68.26 C) 66.91 D) 69.06

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The average marks of a class of 90 students is 126. Out Of them, 4 scores zero, first 60 students scored an average of 116, next 24 scored an average of 118. What is the mark obtained by the remaining student in the class? A) 750 B) 862 C) 774 D) 875

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Last Answer : C) According to the question, 90*126=(4*0)+(60*116)+(24*118)+2y 11340=6960+2832+2y 2y=1548 y=774

The average height of 50 students in a class is 182 cm. 40 students whose average height is 182.5 cm left the class and 50 students whose average height is 180.5 cm joined the class. Find the average height of the present? A) 180.41 B) 175.5 C) 180.55 D) 185.5

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Last Answer : A) The average of the students leaving the class as well as joining the class to be 182 so that the average remains the same. But it is given that the average of the 40 students leaving the class is 182. ... strength of the class. Hence the average of the present class = 182 - 95/60 = 180.5 cm

When a girl weighing 90 kgs left a class, the average weight of the remaining 119 students increased by 400 g. What is the average weight of the remaining 119 students? A) 124 B) 138 C) 145 D) 116

Description : When a girl weighing 90 kgs left a class, the average weight of the remaining 119 students increased by 400 g. What is the average weight of the remaining 119 students? A) 124 B) 138 C) 145 D) 116

Last Answer :  B Let the average weight of the 119 students be X. Therefore, the total weight of the 119 of them will be 119X. The questions states that when the weight of this student who left is added, the total ... , the average weight decreases by 0.4 kgs. (119X+90)/120=X−0.4 ⇒119X+90=120X−48  ⇒X=138

There are two groups of a class consisting of 72 and 88 students respectively. If the average weight of 1st group is 80kg and the weight of 2nd group is 70kg. Find the average weight of whole class? A) 64kg B) 74.5kg C) 84.5kg D) 54kg

Description : There are two groups of a class consisting of 72 and 88 students respectively. If the average weight of 1st group is 80kg and the weight of 2nd group is 70kg. Find the average weight of whole class? A) 64kg B) 74.5kg C) 84.5kg D) 54kg

Last Answer :  B)  Total weight of (72 + 88) = (72*80) + (88 * 70)kg = (5760 + 6160)kg  = 11,920kg  Average weight of the whole class = 11920 / 160  = 74.5 kg

After replacing an old person by a new person, it was found that the average age of five persons of a assembly is the same as it was 6 years ago. What is the difference between the ages of the replaced and the new persons? A) 24 B) 36 C) 30 D) 15

Description : After replacing an old person by a new person, it was found that the average age of five persons of a assembly is the same as it was 6 years ago. What is the difference between the ages of the replaced and the new persons? A) 24 B) 36 C) 30 D) 15 

Last Answer : C) Let the ages of the five persons at present be a, b, c, d & e years. And the age of the new persons be f years. So the new average of five members' age = (a + b + c + d + f)/5 - ... - e + f) = 5x Solving e - f = 30 years. Thus the difference of ages between replaced and new person = 30years.

The average of marks obtained by 60 students in a computer examination is 18. If the average marks of passed students is 20and that of the failed students is 8, what is the number of students who passed the examination? A) 100 B) 75 C) 50 D) 85

Description : The average of marks obtained by 60 students in a computer examination is 18. If the average marks of passed students is 20and that of the failed students is 8, what is the number of students who passed the examination? A) 100 B) 75 C) 50 D) 85 

Last Answer : C Let the number of passed students be x. Then total marks = 60 × 18= 20x + (60– x) × 8 1080= 20x + 480– 8x 12x = 600 ∴ x = 50 ∴ number of passed students = 50

The average age of a morning class is 108, if the average age of 72 ladies in the class is as same as the total average and the number of gents in the class is 2 more than the ladies in the class, what is the average age of gents in the class? A) 152 B) 108 C) 156 D) 154

Description : The average age of a morning class is 108, if the average age of 72 ladies in the class is as same as the total average and the number of gents in the class is 2 more than the ladies in the class, what is the average age of gents in the class? A) 152 B) 108 C) 156 D) 154 

Last Answer : B) According to question, (72+74)X=72×108+74X 146x-74x=7776 72x=7776 X=7776/72= 108years

The average weather(rainfall) for the first 6 days out of 8 days recorded to be 9 cm. The rainfall on last 2 days was in the ratio 2:3. the average of 8 days was 14.2 cm. What was the rainfall on the last day? A) 7.8 B) 34.4 C) 35.76 D) 8.9

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The average age of A and B is 20 years. If C were to replace A, the average would be 19 and id C were to replace B,the average would be 21 . The ages of A, B and C are (in years) (a) 22, 17,16 (b) 22, 18, 20 (c) 30, 18, 15 (d) 23, 17 ,15

Description : The average age of A and B is 20 years. If C were to replace A, the average would be 19 and id C were to replace B,the average would be 21 . The ages of A, B and C are (in years) (a) 22, 17,16 (b) 22, 18, 20 (c) 30, 18, 15 (d) 23, 17 ,15

Last Answer : 22, 18, 20 Hint : A + B = 2 x 20 C + B = 2 x 19 A + C = 2 x 21

A batch of 50 people has the oldest person with 160 years of age. The average of the batch is reduced by 2, if the oldest person is replaced by someone new, Find the age of the new person. A) 45 B) 30 C) 60 D) 75

Description : A batch of 50 people has the oldest person with 160 years of age. The average of the batch is reduced by 2, if the oldest person is replaced by someone new, Find the age of the new person. A) 45 B) 30 C) 60 D) 75

Last Answer : Answer: C)  Average=Sum of observations/Number of observations Given, a batch of 50 people has the oldest person with 160 years of age. Let the average of the group be a'. Sum total of ages = 50 a Given, average of the ... person be b' . 50a - 160 + b = 50(a - 2) b= 160-100 b = 60 years

At the average age of siva and sasi is equal to the average age of somu and ramu. if the ratio of age of siva and sasi 1:3 and somu age is equal to the three by two of siva age. What is the present age of somu if ramu age is 25years? A) 12 B) 15 C) 18 D) 21

Description : At the average age of siva and sasi is equal to the average age of somu and ramu. if the ratio of age of siva and sasi 1:3 and somu age is equal to the three by two of siva age. What is the present age of somu if ramu age is 25years? A) 12 B) 15 C) 18 D) 21

Last Answer : B) siva:sasi=x:3x siva+sasi/2=somu + ramu/2 X+3X=3/2×X+25 5X=50 X=10 Siva’s age is 10 then somu's age = 3/2×10=15 years

The average height of 60 girls was calculated to be 300 cm. It was detected later that one value of 330 cm was wrongly copied as 270 cm for the computation of the mean. Find the correct mean. A) 301cm B) 300.5cm C) 307cm D) 311cm

Description : The average height of 60 girls was calculated to be 300 cm. It was detected later that one value of 330 cm was wrongly copied as 270 cm for the computation of the mean. Find the correct mean. A) 301cm B) 300.5cm C) 307cm D) 311cm

Last Answer : A) Calculated average height of 60 girls = 300cm. Incorrect sum of the heights of 60 girls = (300 60)cm = 18000 cm. Correct sum of the heights of 60 girls = (incorrect sum) - (wrongly copied item) ... 330) cm = 18060cm. Correct mean = correct sum/number of girls = (18060/60) cm = 301 cm.

11 girls went to a canteen. 10 of them spent 10 each and the 11th girl spent 25 more than the average expenditure of all. Find the total money spent by them? A) 172 .5 B) 178 .5 C) 137.5 D) 165.5

Description : 11 girls went to a canteen. 10 of them spent 10 each and the 11th girl spent 25 more than the average expenditure of all. Find the total money spent by them? A) 172 .5 B) 178 .5 C) 137.5 D) 165.5

Last Answer : C)  Let the average money spent by the 11girls = x  Money spent by the 11th girl = (x + 25)  Money spent by the other 10 girls = (10*10) = 100  Total money spent by the 11 girls = (100 + x + 25) =(x + ... = (x + 125)/ 11 =>10x=125  x =12.5 Total money spent by the 11 girls = 11*12.5 = 137.5.

The average age of the whole class is 12.05 years. The average age of all girls is 12.5 years and the average age of boys is 11.75 years. If the total number of boys is 45 then what is the total number of girls in the class? a) 20 b) 25 c) 30 d) 35 e) 40

Description : The average age of the whole class is 12.05 years. The average age of all girls is 12.5 years and the average age of boys is 11.75 years. If the total number of boys is 45 then what is the total number of girls in the class? a) 20 b) 25 c) 30 d) 35 e) 40

Last Answer : Let the number of girls be x. The number of boys is 45. :. Total age of boys and girls in the class = (x+45) × 12.05 or, (x+45) × 12.05 = 45 × 11.75 + x × 12.5 or, 12.05x + 542.25 = 528.75 + 12.5x or, 13.5 = 0.45x or, x = 13.5/0.45 = 30 Answer is: c)

The average price of 12 note books is Rs.15 while the average price of 10 of these note books is Rs.13. Of the remaining 2 note books, if the price of one note book is 50% more than the price of the other, what is the price of each of these two note books? A) Rs. 30, Rs.20 B) Rs. 8, Rs. 30 C) Rs. 10, Rs. 16 D) Rs. 12, Rs. 20

Description : The average price of 12 note books is Rs.15 while the average price of 10 of these note books is Rs.13. Of the remaining 2 note books, if the price of one note book is 50% more than the price of the other, what is the price of ... Rs. 30, Rs.20 B) Rs. 8, Rs. 30 C) Rs. 10, Rs. 16 D) Rs. 12, Rs. 20

Last Answer : Answer: A) Total price of 12 note books = Rs. 180  Total price of 10 note books= Rs. 130 ⇒ The price of 2 note books = Rs. 50 Let the price of each book be x and y. ⇒ x + y = 50 ----- ... note book is 50% more than the other price 150y/100+y=50  y=20 Substituting y value in (1) we get, x=30

Number of students in 4th and 5th class is in the ratio 6 : 11. 40% in class 4 are girls and 48% in class 5 are girls. What percentage of students in both the classes are boys? A) 62.5% B) 54.8% C) 52.6% D) 55.8% E) 53.5%

Description : Number of students in 4th and 5th class is in the ratio 6 : 11. 40% in class 4 are girls and 48% in class 5 are girls. What percentage of students in both the classes are boys? A) 62.5% B) 54.8% C) 52.6% D) 55.8% E) 53.5%

Last Answer : Answer: B Total students in both = 6x+11x = 17x Boys in class 4 = (60/100)*6x = 360x/100 Boys in class 5 = (52/100)*11x = 572x/100 So total boys = 360x/100 + 572x/100 = 932x/100 = 9.32x % of boys = [9.32x/17x] * 100=54.8%

The average height of a batch is 344 cm. 16more students with an average height of 320 cm joined the batch therefore decreasing the average height of the batch by 12 cm. Find the total strength of the batch? A) 12 B) 11 C) 14 D) 16

Description :  The average height of a batch is 344 cm. 16more students with an average height of 320 cm joined the batch therefore decreasing the average height of the batch by 12 cm. Find the total strength of the batch? A) 12 B) 11 C) 14 D) 16 

Last Answer : Answer: D) let the initial strength of the batch be X total height of the batch initially = 344X total height of 16 new students = 320 * 16 = 5120 cm Then, the average height of X+ 16students = 332  332 = [5120 + 344 X]/ [X + 16]  X= 16 students

The average height of the students in a group was 360cm. When 10 students whose height is 292.8cm are newly admitted. The average height of the group was reduced by 24cm.How many students are present in the group? A) 29 B) 25 C) 28 D) 14

Description : The average height of the students in a group was 360cm. When 10 students whose height is 292.8cm are newly admitted. The average height of the group was reduced by 24cm.How many students are present in the group? A) 29 B) 25 C) 28 D) 14

Last Answer : Answer: C) let the number of students initially in the class be A, then, total height = A * 360------ 1 again the no of students increased = A + 10 then, total height A + 10 student = (A +10) * 336 ... 3 (A+10) *336-2928 =A*360 336A+3360-2928=360A A=18 Number of students in class = 18+10=28

The average scores of a batch of students in a test is 84. The 36% of students's average score is 57 and 42% of students's score is 84. Then find the average score of remaining 22% of students approximately, A) 128 B) 131 C) 119 D) 106

Description : The average scores of a batch of students in a test is 84. The 36% of students's average score is 57 and 42% of students's score is 84. Then find the average score of remaining 22% of students approximately, A) 128 B) 131 C) 119 D) 106 

Last Answer : Answer: A)  let the number of students be 100, then, 100*84 = 36*57 + 42*84 + 22*x 22x = 8400-2052-3528 x = 128.18

Students of two university appeared for a common test of maximum 60 marks. The average of their marks for university 1 & university 2 are 39 & 42 respectively. If the no of students of university 1 is twice the no of students of university 2. Then what is the average marks of all students of both the university? A) 40 B) 42 C) 26 D) 36

Description : Students of two university appeared for a common test of maximum 60 marks. The average of their marks for university 1 & university 2 are 39 & 42 respectively. If the no of students of university 1 is twice the no ... the average marks of all students of both the university? A) 40 B) 42 C) 26 D) 36

Last Answer : Answer: A) Let number of students of university2 be N and the no of students of university 1 be 2N the average of university1 and university 2 is 39 and 42 total marks of university 1 students and university 2 ... 78N and N*42 =42N average of both university,  =(78N+42N) /(N+2N) = 40 marks

The average state of the city in the first 4 days of a month was 116 degrees. The average for the second, third, fourth and fifth days was 120 degrees. If the state of the first and fifth days were in the ratio 7:8 then what is the state on the fifth day. A) 112degrees B) 128degrees C) 132degrees D) 130degrees

Description : The average state of the city in the first 4 days of a month was 116 degrees. The average for the second, third, fourth and fifth days was 120 degrees. If the state of the first and fifth days ... :8 then what is the state on the fifth day. A) 112degrees B) 128degrees C) 132degrees D) 130degrees

Last Answer :  B)  Sum of states on 1st, 2nd, 3rd, 4th days = (116 *4) = 464 =======>A Sum of states on 2nd, 3rd, 4th and 5th days = (120 * 4)= 480 ======>b From a and b Subtracting each other ... be 7x and 8x degrees respectively Then 8x - 7x = 16 x = 16 therefore state on the 5th day = 8x = 128 degrees.

When the average age of a father, mother and their son was 90 years, the son got married and a child was born just 6 year after the marriage when child turned 14 years the average age of the family is 80yrs. Find the age of daughter - in - law at present? A) 55 B) 56 C) 57 D) 58

Description : When the average age of a father, mother and their son was 90 years, the son got married and a child was born just 6 year after the marriage when child turned 14 years the average age of the family is 80yrs. Find the age of daughter - in - law at present? A) 55 B) 56 C) 57 D) 58

Last Answer : B) total age of father, mother and son at the time of son's marriage = 90*3 =270 present age of family father, mother, son, daughter-in-law, child = (father, mother, son age at the time of marriage ... 60)+ daughter-in-law present age + 14 = 80*5 =400 daughter-in-law present age= 400-344 = 56yrs

Monica's average expenses for 4 days is Rs 6.0. She spent Rs 7.70 on first day, Rs 6.30 on second day. If she spent 10 on third day , How much did she spend on the 4th day? (a) Rs 2 (b) Rs 3 (c) Rs 4 (d) Rs 0

Description : Monica's average expenses for 4 days is Rs 6.0. She spent Rs 7.70 on first day, Rs 6.30 on second day. If she spent 10 on third day , How much did she spend on the 4th day? (a) Rs 2 (b) Rs 3 (c) Rs 4 (d) Rs 0 

Last Answer : Rs 0 Hint : Required Amount = 24 - ( 7.70 + 6.30 + 10)