# If the Sum of the Mean and Variance of a Binomial Distribution for 6 Trials is 10 3 , Find the Distribution. - Mathematics

If the sum of the mean and variance of a binomial distribution for 6 trials is $\frac{10}{3},$  find the distribution.

#### Solution

Given that n = 6
The sum of mean and variance of a binomial distribution for 6 trials is $\frac{10}{3}$

$\Rightarrow 6p + 6pq = \frac{10}{3}$
$\Rightarrow 18p + 18p(1 - p) = 10$
$\Rightarrow 18 p^2 - 36p + 10 = 0$
$\Rightarrow (3p - 1)(6p - 10) = 0$
$\Rightarrow p = \frac{1}{3}\text{ or } \frac{5}{3}$
$p = \frac{5}{3} (\text{ Neglected as it is greater than 1} )$
$\therefore p = \frac{1}{3}$
$\Rightarrow q = 1 - p = \frac{2}{3}$
$\text{ Hence, the distribution is given by }$
$P(X = r) =^{6}{}{C}_r \left( \frac{1}{3} \right)^r \left( \frac{2}{3} \right)^{6 - r} , r = 0, 1, 2 . . . . . 6$

Concept: Bernoulli Trials and Binomial Distribution
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#### APPEARS IN

RD Sharma Class 12 Maths
Chapter 33 Binomial Distribution
Exercise 33.2 | Q 19 | Page 25