If the arithmetic mean of 7, 5, 13, x and 9 is 10, then the value of x is :

Answer: Option D

Arithmetic mean
$$\frac{\text{Total sum}}{\text{Total number}}$$
According to the question,
⇒ 10 = $$\frac{7+5+13+x+9}{5}$$
⇒ 50 = x + 34
⇒ x = 50 - 34
⇒ x = 16