• # question_answer 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 average height of all of them is A)  1 m 12 cm        B)  1 m 12.1 cm C)  1 m 21.1 cm     D)  1 m 21 cm

[b] Average height = $\frac{6\times (1.15)+8\times (1.10)+6(1.12)}{20}$ $\Rightarrow \frac{22.42}{20}=1.121\,\,or\,\,1\,\,m\,12.1\,\,cm$