Two balls are drawn at  a random with replacement from a box containing 10 black and 8 red balls. Find the probability that i. both the balls are red. Ii. first ball is black and second is red. iii. One of them is black and other is red.

Explanation

Given:

Total number of balls =18
Number of red balls =8
Number of black balls =10
So, (i) Probability of getting a red ball in the first draw `=frac{8}{18}=frac{4}{9}`

The ball has been replaced after the first draw.

therefore, Probability of getting a red ball in the second draw `=frac{8}{18}=frac{4}{9}`

Therefore, probability of getting both the balls red `=frac{4}{9} times frac{4}{9}=frac{16}{81}=0.19`

...