What is the average (aritmetic mean) hight of the n people in a certain group?

1 the average hight of the n/3 talles people in the group is 6 feet and 2 1/2 inches and the average hight of the rest of the people in the group is 5 feet and 10 inches.

2 The sum of the lenghts of the people is 178 feet and 9 inches.









Note - if you have the averages of all the FRACTIONS or PERCENTAGES of a group, then you'll be able to calculate the overall average of the group. This is a worthwhile fact to memorize for the data sufficiency problems.


stmt 1) Convert feet to inches..

[(n/3)(74.5) + (2n/3)(70)] / (n)
Suff

Stmt 2) Suff


Ans - D