The average height of 30 girls out of a class of 40 is 160 cm. and that of the remaining girls is 156 cm. The average height of the whole class is :
Choose the correct option: A) 158 cms B) 158.5 cms C) 159 cms D) 159.5 cms E) none
Explanation:   Average height of the whole class =(36×160+10×156/40)=159 cms   Answer 159 cms
<result>C</result>
The average height of 30 girls out of a class of 40 is 160 cm. and that of the remaining girls is 156 cm. The average height of the whole class is :