Question

A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is ______.

विकल्प

• `6/25`

• `12/5`

• 6

• 4

Answer 1

A box contains 15 green and 10 yellow balls. If 10 balls are randomly drawn, one-by-one, with replacement, then the variance of the number of green balls drawn is `underline(12/5)`.

Explanation:

Probability of green ball (p) `=15/25=3/5`

Probability of yellow ball (q) `=10/25=2/5`

Also, n = 10

∴ Variance = npq

`=10(3/5)(2/5)`

`=12/5`