The average height of 15 boys out of a class of 50 is 160 cm. If the average height of the remaining boys is 168 cm, the average height (in cm) of all the boys of the class is:​

Correct option is B

Given:

Average height of 15 boys = 160 cm

Average height of remaining 35 boys = 168 cm

Total number of boys = 50

Formula Used:

Average = $$\frac{(A_1 \times N_1) + (A_2 \times N_2)}{N_1 + N_2}$$

A₁ and A₂ are Average height 

N₁ and N₂ are number of boys

Solution:

Sum of first 15 boys = 160 × 15 = 2400 cm

Sum of remaining 35 boys = 168 × 35 = 5880 cm

Total sum = 2400 + 5880 = 8280 cm

Average height = $$\frac{8280}{50}$$​ = 165.6 cm