Question

) A bag contains white, black and red balls only. A ball is drawn at random from the
bag. If the probability of getting a white ball is, and that of a black ball is, then
10
find the probability of getting a red ball. If the bag contains 20 black balls, then find
the total number of balls in the bag.
3​

Answer 1

Answer:

5/9

Step-by-step explanation:

Solution:

Let E1 : transferred ball is red.

E2 : transferred ball is black.

A : Getting both red from 2nd bag (after transfer)

P(E1)=3/7,P(E2)=4/7

P(A/E1) = 5c2/10c2=2/9

,P(A/E2) = 4c2/10c2=2/15

P(E1/A) = ((P(E1) P(A|E1))/ P(E1)P(A|E1)+P(E2)P(A|E2)

= 5/9