A Police man fires six bullets on a decoit. The probability that the decoit will be killed by one bullet is 0.6. What is the probability that the -Maths 9th

1 Answer

Answer :

Let Ai be the event that the decoit is killed by the ith bullet (1 ≤ i ≤ 6). Then \(\bar{A}_i\) is the event that the decoit is not killed, ∴ P (Ai) = 0.6 and P(\(\bar{A}_i\)) = 1 − 0.6 = 0.4∴ Probability of the decoit being still alive= P(\(\bar{A}_1\))  P(\(\bar{A}_2\))  P(\(\bar{A}_3\))  P(\(\bar{A}_4\))  P(\(\bar{A}_5\))  P(\(\bar{A}_6\)) = 0.4 × 0.4 × 0.4 × 0.4 × 0.4 × 0.4 = 0.004096.Note. Using simpler notation, we may write success : Bullet will hit the decoit p = 0.6 ⇒ q = 1 − p = 1 − 0.6 = 0.4Required probability = qqqqqq = (q)6 = (0.4)6.

Related questions

Description : Three of the six vertices of a regular hexagon are chosen at random. The probability that the triangle with these vertices is equilateral equals : -Maths 9th

Last Answer : (c) \(rac{1}{10}\)Let S be the sample space.Then n(S) = Number of triangles formed by selecting any three vertices of 6 vertices of a regular hexagon= 6C3 = \(rac{6 imes5 imes4}{3 imes2}\) = 20.Let A : Event that the ... Required probability = \(rac{n(A)}{n(S)}\) = \(rac{2}{20}\) = \(rac{1}{10}\).

Description : A fair dice is thrown twenty times. The probability that on the tenth throw the fourth six appears is -Maths 9th

Last Answer : (c) \(rac{84 imes5^6}{6^{10}}\)In the first nine throws we should have three sixes and six non-sixes and a six in the tenth throw and thereafter whatever face appears, it doesn't matter. ∴ Required probability = 9C3 \(\bigg(rac{1} ... x 1 x 1 ............x 1 {10 times} = \(rac{84 imes5^6}{6^{10}}\).

Description : A man can hit a target once in 4shots. If he fires 4 shots in succession, what is the probability that he will hit his target? a) 175/256 b) 81/256 c) 1/256 d) 1/256

Last Answer : a) 175/256

Description : From a group of 3 man and 2 women, two person are selected at random. Find the probability that at least one women is selected. -Maths 9th

Last Answer : (b) \(rac{7}{10}\)Total number of ways of selecting 2 persons at random out of 5 persons = 5C2 ∴ n(S) = 5C2 = \(rac{|\underline5}{|\underline3|\underline2}\) = \(rac{5 imes4}{2 imes1}\) = 10Let A : Event of selecting ... = 2 3 + 1 = 7 ∴ Required probability = \(rac{n(A)}{n(S)}\) = \(rac{7}{10}\).

Description : Suppose that, instead of bouncing off the floor and into the chair, the bullet had hit someone and killed them. What rationalization would gun advocates use to defend this guy?

Last Answer : It’s too bad he didn’t shoot off his manhood. At least that way he couldn’t reproduce.

Description : If the probability of winning a race of an athlete is 1 / 6 less than the twice the probability of losing the race. -Maths 9th

Last Answer : Let probability of winning the race be p Probability of losing the race = 1 - p According to the statement of question, we have p = 2 (1 - p) - 1 / 6 ⇒ 6p = 12-12p -1 ⇒ 18p = 11 ⇒ p = 11 / 18 Hence, probability of winning the race is 11 / 18

Description : If the probability of winning a race of an athlete is 1 / 6 less than the twice the probability of losing the race. -Maths 9th

Last Answer : Let probability of winning the race be p Probability of losing the race = 1 - p According to the statement of question, we have p = 2 (1 - p) - 1 / 6 ⇒ 6p = 12-12p -1 ⇒ 18p = 11 ⇒ p = 11 / 18 Hence, probability of winning the race is 11 / 18

Description : An integer is chosen at random from the first two hundred positive integers. What is the probability that the integer chosen is divisible by 6 or 8 ? -Maths 9th

Last Answer : As there are 200 integers, total number of exhaustive, mutually exclusive and equally likely cases, i.e, n(S) = 200 Let A : Event of integer chosen from 1 to 200 being divisible by 6⇒ n(A) = 33 \(\bigg(rac{200}{6}=33rac{1}{3}\ ... (rac{25}{200}\) - \(rac{8}{200}\) = \(rac{50}{200}\) = \(rac{1}{4}\).

Description : Among 15 players, 8 are batsman and 7 are bowlers. Find the probability that a team is chosen of 6 batsman and 5 bowlers ? -Maths 9th

Last Answer : The chosen consists of players (6 + 5). ∴ Number of ways of selecting 11 players out of 15 players = n(S) = 15C11 Let A : Event of choosing 6 batsmen of 8 batsmen and 5 bowlers of 7 bowlers Then, n(A) = 8C6 ... 7 imes6}{2}\) x \(rac{4 imes3 imes2 imes1}{15 imes14 imes13 imes12}\) = \(rac{28}{65}.\)

Description : 6 boys and 6 girls are sitting in a row randomly. The probability that boys and girls sit alternately is -Maths 9th

Last Answer : (b) \(rac{1}{462}\)Let S be the sample space. Then, n(S) = Number of ways in which 6 boys and 6 girls can sit in a row = 12! Let E : Event of 6 girls and 6 boys sitting alternately. Then, the ... )= \(rac{2 imes6 imes5 imes4 imes3 imes2 imes1}{12 imes11 imes10 imes9 imes8 imes7}\) = \(rac{1}{462}\).

Description : 6 boys and 6 girls are seated in a row. Probability that all the boys sit together is -Maths 9th

Last Answer : (d) \(rac{1}{132}\)Let S be the sample space for arranging 6 boys and 6 girls in a row. Then, n(S) = 12! If all 6 boys are to sit together, then consider the 6 boys as one entity. Now the ... ) = \(rac{7 imes6 imes5 imes4 imes3 imes2}{12 imes11 imes10 imes9 imes8 imes7}\) = \(rac{1}{132}\).

Description : The odds against certain event are 5:2 and the odds in favour of another in dependent event are 6:5. The probability that at least one of -Maths 9th

Last Answer : (c) \(rac{52}{77}\)Given, odds against Event 1 = 5 : 2⇒ P(Event 1 not happening) = \(rac{5}{5+2}\) = \(rac{5}{7}\)Odds in favour of Event 2 = 6 : 5⇒ P(Event 2 happens) = \(rac{6}{6+5}\) = \( ... }\)(∵ Both event are independent)⇒ P(At least one event happens) = 1 - \(rac{25}{77}\) = \(rac{52}{77}\).

Description : There are five acquaintances. One of them shot and killed one of the other five. Which man is the murderer? 1. Dan ran in the NY City marathon yesterday with one of the innocent men. 2. Mike ... last computers together. 9. The murderer is Jack's brother; they grew up together in Seattle. -Riddles

Last Answer : 1. Jack is not the murderer, because he is the brother of the murderer. 2. Dan can't be the murderer since he ran a marathon, and the murderer recently had his leg amputated, and wouldn't ... must also be alive since Jeff plans to install Ben's computer next week. This means that Jeff killed Mike.

Description : The probability that Dimpu gets scholarship is 0.9 and Pintu will get is 0.8. What is the probability that at least one of them gets the scholarship. -Maths 9th

Last Answer : Let A be the event that Dimpu gets scholarship and B the event that Pintu gets scholarship. It is given that P (A) = 0.9, P (B) = 0.8. The probability that none of them gets the scholarship = (1 − 0.9) ... .2 = 0.02 ∴ The probability that at least one of them gets the scholarship = 1 − 0.02 = 0.98.

Description : A five digit number is formed by the digits 0, 1, 2, 3, 4 (without repetition). Find the probability that the number formed is divisible by 4 ? -Maths 9th

Last Answer : Without repetition, a five -digit number can be formed using the five digits in 5! ways (5 4 3 2 1) Out of these 5! numbers, 4! numbers will be starting with digit 0. (0 (fixed) 4 3 2 1) ∴ Total ... + 6 + 6 + 4 + 4 + 4 = 30∴ Required probability = \(rac{30}{96}\) = \(rac{5}{16}.\)

Description : A determinant of second order is made with the elements 0, 1. What is the probability that the determinant is positive? -Maths 9th

Last Answer : (c) \(rac{3}{16}\)Total number of determinants that can be formed using 0 and 1 = 16 (4 4)The positive determinants are \(\begin{bmatrix}1&0\[0.3em]1&1nd{bmatrix}\),\(\begin{bmatrix}1&0\[0.3em]0&1nd{ ... bmatrix}1&1\[0.3em]0&1nd{bmatrix}\), i.e, 3 in number.∴ Required probability = \(rac{3}{16}.\)

Description : If an integer P is chosen at random in the interval 0 ≤ p ≤ 5, the probability that the roots of the equation x^2 + px -Maths 9th

Last Answer : answer:

Description : A man was found dead next to a 13 story building. The police say it was a suicide, but you say it was a homicide (someone killed him). To prove this, you go to each floor on the building, open ... 13th floor, open the window, and toss a penny out. How does this prove it wasn't a suicide? -Riddles

Last Answer : If the man committed suicide, he would've left the window open and you wouldn't have had to open it.

Description : a muder had been suspected but the police did not know how the man had been killed since there had been no windows no doors no chairs no desks the was only a puddle left on the floor in the mans ... reach the ceiling with no promt to get hung up on the celing and why was there a puddle -Riddles

Last Answer : the man had waited on a ice cube and the ice cube had melted and left a puddle

Description : Find six rational numbers between 5/7 and 6/7. -Maths 9th

Last Answer : Solution :-

Description : A coin is tossed 500 times and we get Heads : 285 and tails : 215 times. When a coin is tossed at random, what is the probability of getting a. head? b. tail? -Maths 9th

Last Answer : Given, Total number of events = 500 No. of times heads occur = 285 Probability of getting head when coin is tossed at random = 285/500 = 57/100 No. of times tails occur = 215 Probability of getting tails when coin is tossed at random = 215/500 = 43/100

Description : Two coin are tossed 400 times and we get a. Two Heads : 112 times b. One Head : 160 times c. No Head : 128 times. When two coins are tossed at random, what is the probability of getting a. Two Heads b. One Head c. No Head -Maths 9th

Last Answer : Given, Total number of events = 400 (a) No. of times two heads occur = 112 Probability of getting two heads = 112/400 = 7/25 (b) No. of times one heads occur = 160 Probability of getting one heads = 160/400 = 2/5 (c) No. of times no heads occur = 128 Probability of getting no heads = 128/400 = 8/25

Description : The probability of guessing the correct answer to a certain question is x/ 2. -Maths 9th

Last Answer : Here, probability of guessing the correct answer = x / 2 And probability of not guessing the correct answer = 2 / 3 Now, x / 2 + 2 / 3 = 1 ⇒ 3x + 4 = 6 ⇒ 3x = 2 ⇒ x = 2 / 3

Description : In a throw of a die, find the probability of not getting 4 or 5. -Maths 9th

Last Answer : Required probability = 1 – P(4) – P(5) =1- 1 / 6 - 1 / 6 = 4 / 6 = 2 / 3

Description : In a class, there are x girls and y boys, a student is selected at random, then find the probability of selecting a boy. -Maths 9th

Last Answer : Number of boys = y Total students = (x + y) Thus,P(a boy)= y/(x+y)

Description : 750 families with 3 children were selected randomly and the following data recorded If a family member is chosen at random, compute the probability that it has : -Maths 9th

Last Answer : (i) P(no boy child) =100 / 750 = 2 / 15 (ii) P (no girl child) = 120 /750 =4 / 25

Description : A coin is tossed 500 times and we get Heads : 285 and tails : 215 times. When a coin is tossed at random, what is the probability of getting a. head? b. tail? -Maths 9th

Last Answer : Given, Total number of events = 500 No. of times heads occur = 285 Probability of getting head when coin is tossed at random = 285/500 = 57/100 No. of times tails occur = 215 Probability of getting tails when coin is tossed at random = 215/500 = 43/100

Description : Two coin are tossed 400 times and we get a. Two Heads : 112 times b. One Head : 160 times c. No Head : 128 times. When two coins are tossed at random, what is the probability of getting a. Two Heads b. One Head c. No Head -Maths 9th

Last Answer : Given, Total number of events = 400 (a) No. of times two heads occur = 112 Probability of getting two heads = 112/400 = 7/25 (b) No. of times one heads occur = 160 Probability of getting one heads = 160/400 = 2/5 (c) No. of times no heads occur = 128 Probability of getting no heads = 128/400 = 8/25

Description : The probability of guessing the correct answer to a certain question is x/ 2. -Maths 9th

Last Answer : Here, probability of guessing the correct answer = x / 2 And probability of not guessing the correct answer = 2 / 3 Now, x / 2 + 2 / 3 = 1 ⇒ 3x + 4 = 6 ⇒ 3x = 2 ⇒ x = 2 / 3

Description : In a throw of a die, find the probability of not getting 4 or 5. -Maths 9th

Last Answer : Required probability = 1 – P(4) – P(5) =1- 1 / 6 - 1 / 6 = 4 / 6 = 2 / 3

Description : In a class, there are x girls and y boys, a student is selected at random, then find the probability of selecting a boy. -Maths 9th

Last Answer : Number of boys = y Total students = (x + y) Thus,P(a boy)= y/(x+y)

Description : 750 families with 3 children were selected randomly and the following data recorded If a family member is chosen at random, compute the probability that it has : -Maths 9th

Last Answer : (i) P(no boy child) =100 / 750 = 2 / 15 (ii) P (no girl child) = 120 /750 =4 / 25

Description : Can the experimental probability of an event be a negative number? -Maths 9th

Last Answer : No, because the number of trials in which the event can happen cannot be negative and the total number of trials is always positive.

Description : Can the experimental probability of an event be greater than 1? -Maths 9th

Last Answer : No, as the number of trials can't be greater than the total number of trials.

Description : In a throw of a die, find the probability of getting an even number. -Maths 9th

Last Answer : Total even number on a die = 3 P (getting an even numbers) = 3/6 = 1/2

Description : A die is thrown.What is the probability of getting a multiple of 3 on the upper face ? -Maths 9th

Last Answer : Multiple of 3 on a die = 3, 6 ∴ P (a multiple of 3) = 2/6 = 1/3.

Description : In a single throw of two dice, what is the probability of getting a sum of 9? -Maths 9th

Last Answer : Outcomes with sum of 9 = { (3, 6), (4, 5), (5, 4), (6, 3) } P ( getting a sum of 9 is ) = 4/36 = 1/9

Description : MCQ Questions for Class 9 Maths Chapter 15 Probability with answers -Maths 9th

Last Answer : Below you will find MCQ Questions of Chapter 15 Probability Class 9 Maths Free PDF Download that will help you in gaining good marks in the examinations and also cracking competitive exams. These ... . These Probability MCQ Questions will help you in practising more and more questions in less time.

Description : What do you mean by probability? -Maths 9th

Last Answer : It is the chance of happening of an event when measured quantitatively.

Description : Two dice are thrown. Find the probability of getting an odd number on the first die and a multiple of 3 on the other. -Maths 9th

Last Answer : Let A : Getting an odd number on first die; B : Getting a multiple of 3 on second die, thenA = {1, 3, 5}, B = {3, 6} ∴ P(A) = \(rac{3}{6}=rac{1}{2}\), P(B) = \(rac{2}{6}=rac{1}{3}\) ... B are independent∴ Required probability = P (A) . P (B) = \(rac{1}{2}\) x \(rac{1}{3}\) = \(rac{1}{6}\)

Description : A husband and a wife appear in an interview for two vacancies in the same post. The probability of husband‘s -Maths 9th

Last Answer : Let A : Event of husband being selected B : Event of wife being selectedThen P(A) = \(rac{1}{7},\) P(B) = \(rac{1}{5}\)P(\(\bar{A}\)) = 1 - \(rac{1}{7}\) = \(rac{6}{7}\), P(\(\bar{B}\)) = 1 - ... {24}{35}\)(iv) P(at least one selected) = 1 - P(none selected) = 1 - \(rac{24}{35}\) = \(rac{11}{35}\)

Description : A can solve 90% of the problems given in a book and B can solve 70%. What is the probability that at least one of them -Maths 9th

Last Answer : Let E be the event that A solve the problem and F the event that B solves the problem.Then P(E) = \(rac{90}{100}\) = \(rac{9}{10}\), P(F) =\(rac{70}{100}\) = \(rac{7}{10}\), P(\(\bar{E}\) ... probability that at least one of them will solve a problem = 1 - \(rac{3}{100}\) = \(rac{97}{100}\) = 0.97.

Description : A bag contains 5 white, 7 red and 4 black balls. If four balls are drawn one by one with replacement, what is the probability that none is white. -Maths 9th

Last Answer : Let A, B, C, D denote the events of not getting a white ball in first, second, third and fourth draw respectively. Since the balls are drawn with replacement, therefore, A, B, C, D are independent events such that P (A) = P (B) ... x \(rac{11}{16}\) x \(rac{11}{16}\) = \(\big(rac{11}{16}\big)^4.\)

Description : The probability of student A passing examination is 3/7 and of student B passing is 5/7 Assuming the two events “A passes”, -Maths 9th

Last Answer : p1 = P(A) = \(rac{3}{7}\), p2 = P(B) = \(rac{5}{7}\) ∴ q1 = P(\(\bar{A}\)) = 1 - P(A) = 1 - \(rac{3}{7}\) = \(rac{4}{7}\). q2 = P(\(\bar{B}\)) = 1 - P(B) = 1 - \(rac{5}{7}\) = \(rac{2}{7}\) ... passes) = p1 q2 + q1 p2 = \(rac{3}{7}\) x \(rac{2}{7}\) + \(rac{4}{7}\) x \(rac{5}{7}\) = \(rac{26}{49}.\)

Description : What is the definition of probability? -Maths 9th

Last Answer : If in a random experiment there are n mutually exclusive and equally likely elementary events and m of them are favourable to an event A, then the probability P of happening of A denoted by P(A) is ... A}\)) = 1Note : The probabilities of mutually exclusive and exhaustive events always adds up to 1.

Description : Define : Addition Theorem of Probability. -Maths 9th

Last Answer : (a) For Two Events. If A and B are two events associated with a random experiment, then P(A ∪ B) = P(A) + P(B) - P(A ∩ B) ⇒ P(A or B) = P(A) + P(B) - P(A and B) Corollary 1: If A and B are ... that A ⊆ B, then P(A) ≤ P(B) (ii) If E is an event associated with a random experiment, then 0 P(E) ≤ 1

Description : Define : Multiplication Theorem on Probability. -Maths 9th

Last Answer : Statement I. If two events A and B are independent, then probability that they will both occur is equal to the product of their individual probabilities. i.e. P (A and B) = P (A) P (B) ... occurrence of two independent events. Method. Use the relation P (A ∩ B) = P (A) . P (B).

Description : The probability of A, B, C solving a problem are 1/3, 2/7 and 3/8 respectively. -Maths 9th

Last Answer : Let E1, E2, E3 be the eventsthat the problem issolved by A, B, C respectively and let p1, p2, p3 be corresponding probabilities. Then,p1 = P(E1) = \(rac{1}{3}\), p2 = P(E2) = \(rac{2}{7}\), p3 = P(E3) = \(rac{3}{8}\) ... }{8}\) = \(rac{25}{168}\) + \(rac{5}{42}\) + \(rac{5}{28}\) = \(rac{25}{56}.\)

Description : If two coins are tossed once, what is the probability of getting at least one head ? -Maths 9th

Last Answer : When two coins are tossed once, there are four possible outcomes, i.e., S = {HH, HT, TH, TT} ∴ Total number of outcomes = n(S) = 4 Let A : Event of getting at least one head ⇒ A = {HH, HT, TH} ⇒ n(A) = 3∴ P(A) = \(rac{n(A)}{n(S)}\) = \(rac{3}{4}.\)

Description : Two unbiased dice are rolled. Find the probability of getting a multiple of 2 on one die and a multiple of 3 on the other die ? -Maths 9th

Last Answer : When two unbiased dice are rolled, the possible out comes are∴ n(S) = 36 Let A : getting a multiple of 2 on one die and a multiple of 3 on the other die. ⇒ A = {(2, 3), (2, 6), (4, 3), (4, 6), (6, 3), (6, 6), (3, 2), ( ... (3, 6), (6, 2), (6, 4)} ⇒ n(A) = 11∴ P(A) = \(rac{n(A)}{n(S)} =rac{11}{36}.\)