If the probability that a man aged 60 will live to be 70 is 0.65, what is the probability that out of 10 men, now 60, at least 8 will live to be 70?


The probability that a man aged 60 will live to be 70 is 0.65


Using Bernoulli’s Trial we have,


P(Success=x) = nCx.px.q(n-x)


x=0, 1, 2, ………n and q = (1-p), n =8


p = 0.65 q =0.35


Probability that out of 10 men, now 60, at least 8 will live to be 70 is: P(8) + P(9) + P(10)


10C8(0.65)8(0.35)2 + 10C9(0.65)9(0.35)1 + 10C10(0.65)10(0.35)0


⇒ 0.2615


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