Q56 / 90 · JEE Main 2017 (02 Apr) · Mathematics

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:

Correct answer
A
$\frac{12}{5}$
B
$6$
C
$4$
D
$\frac{6}{25}$

Solution

For Bernoulli's trials

Variance $= n . p . q$

Given, number of trials $n = 10$

Probability of drawing a green ball $p = \frac{15}{25} = \frac{3}{5}$ and $q = \frac{2}{5}$

Hence, Variance $= 10 \times \frac{3}{5} \times \frac{2}{5} = \frac{12}{5}$

Hence, the correct answer is option: 'A'.

Relevant Questions

A set of four observations has mean and variance . Another set of six observations has mean and variance . Then, the variance of all these o08 Apr, 2026 (E)Measures of Dispersion
Let the mean and the variance of seven observations , , be and respectively. Then the quadratic equation whose roots are and is :06 Apr, 2026 (E)Measures of Dispersion
For observations , if and , then their standard deviation is:04 Apr, 2026 (E)Measures of Dispersion
The mean and variance of 10 observations are 9 and 34.2, respectively. If 8 of these observations are , then the mean deviation about the me28 Jan, 2026 (M)Measures of Dispersion
The mean and variance of a data of 10 observations are 10 and 2, respectively. If an observations in this data is replaced by , then the mea24 Jan, 2026 (M)Measures of Dispersion
Let the mean and variance of 8 numbers be and , respectively. Then the mean of 4 numbers is :23 Jan, 2026 (M)Measures of Dispersion

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:

Solution

Relevant Questions

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: