Question

In a blindfolded game, a boy can hit the target 8 times out of 12. If he fired 8 shots, find out the probability of more than 4 hits?

(a) 2.530

(b) 0.1369

(c) 0.5938

(d) 3.998

This question was addressed to me by my school teacher while I was bunking the class.

I want to ask this question from Counting topic in chapter Counting of Discrete Mathematics

Answer 1

Correct option is (c) 0.5938

To explain I would say: Here, n = 8, p = 0.6, q = 0.4. Suppose X = number of hits x0 = 0 number of hits, x1 = 1 hit, x2 = 2 hits, and so on.

So, (X) = P(x5) + P(x6) + P(x7) + P(x8) = ^8C5(0.6)^5(0.4)^3 + ^8C5(0.6)^6(0.4)^2 + ^8C7(0.6)^7(0.4)^1 + ^8C8(0.6)^8(0.4)^0 = 0.5938.