Out of 20 boys, 6 are each of 1 m 15 cm height, 8 are of 1 m 10 cm and rest of 1 m 12 cm. The what is the average height of all of them?

[A]1 m 12 cm

[B]1 m 12.1 cm

[C]1 m 21 cm

[D]1 m 21.1 cm

**1 m 12.1 cm**

Average height of all 20 boys =

= 1 m 12.1 cm

Hence option [B] is correct answer.