Q48 of 249 Page 31

Mark the correct alternative in each of the following:

Three person, A, B and C fire a target in turn starting with A. Their probabilities of hitting the target are 0.4, 0.3 and 0.2 respectively. The probability of two hits is


A = Event of Person A hitting the target.


P(A) = 0.4


P = 1 – P(A) = 1 – 0.4


P = 0.6 → (1)


B = Event of Person B hitting the target.


P(B) = 0.3


P = 1 – P(B) = 1 – 0.3


P = 0.7 → (2)


C = Event of Person C hitting the target.


P(C) = 0.2


P = 1 – P(C) = 1 – 0.2


P = 0.8 → (3)


Now then,



= 0.4 × 0.3 × 0.8 + 0.4 × 0.7 × 0.2 + 0.6 × 0.3 × 0.2


= 0.096 + 0.056 + 0.036


= 0.188

More from this chapter

All 249 →
46

Mark the correct alternative in each of the following:

A bag contains 5 red and 3 blue balls. If 3 balls are drawn at random without replacement, then the probability that exactly two of the three balls were red, the first ball being red, is


C. 15/28 D. 5/28


 47

Mark the correct alternative in each of the following:

In a college 30% students fail in Physics, 25% fail in Mathematics and 10% fail in both. One student is chosen at random. The probability that she fails in Physics if she has failed in Mathematics is


 49

Mark the correct alternative in each of the following:

A and B are two students. Their chances of solving a problem correctly are 1/3 and 1/4 respectively. If the probability of their making common error is 1/20 and they obtain the same answer, then the probability of their answer to be current is


 50

Mark the correct alternative in each of the following:

Two cards are drawn from a well shuffled deck of 52 playing cards with replacement. The probability that both cards are queen is