Probability

shilpaqueen wrote:King Solomon and queen Sheeba have 50 silver coins each. Find the probality that one of them donates n silver coins then the other donates n+- 10 silver coins n<=50)

1/50
1/5
9/25
2/5
3/7

OA is 9/25

King and Queen each have 50 coins.

We need to find the probability that if one of them donates n silver coins then the other donates n+- 10 silver coins.

So, when can be this conditions are possible:

When one donates 1 to 10 coins the other do not have a chance to donate n - 10 coins as n < 11.

When one donates 41 to 50 coins the other do not have a chance to donate n + 10 coins as n > 40.

So out of 50 possible values of n, 20 possible values of n will not let the other distribute n+- 10 coins.

Thus, the probality that one of them donates n silver coins then the other donates n+10 silver coins = 1 - (20/50)

= 1 - 2/5

= 3/5

Thus, the probality that one of them donates n silver coins then the other donates n-10 silver coins = 1 - (20/50)

= 1 - 2/5

= 3/5

Thus, the probality that one of them donates n silver coins then the other donates n+-10 silver coins = (3/5)*(3/5) = 9/25