Question

If A is an event of a random experiment such that `"P"("A") : "P"(bar"A")` = 17 : 15 and n(S) = 640 then find n(A)

Answer 1

`"P"(bar"A") = 15/32`

1 − P(A) = `15/32`

⇒ ∴ P(A) = `1 - 15/32`

= `(32 - 15)/32`

= `17/32`

P(A) = `("n"("A"))/("n"("S")) = 17/32`

⇒ `("n"("A"))/640 = 17/32`  ..[Given n(S) = 640]

32 n(A) = 17 × 640

n(A) = `(17 xx 640)/32`

= 17× 20

⇒ n(A) = 340