A random variable X has binomial distribution with n = 10 and p = 0.3 then variance of X is

We know that if X is a random variable under binomial distribution, then

Variance of X is given by

Var(X) = np(1-p)

Thus, in the given question

Var(X) = 10 * 0.3(1-0.3)

Var(X) = 3 * 0.7

Var (X) = 2.1