Bunuel wrote:

(1) The average height of \frac{n}{3} people is 74.5 inches and the average height of \frac{2n}{3} people (the res of the people in the group n-\frac{n}{3}=\frac{2n}{3}) is 70 inches --> average \ height=\frac{sum \ of \ heights}{# \ of \ people}=\frac{74.5*\frac{n}{3}+70*\frac{2n}{3}}{n} --> n cancels out --> average \ height=74.5*\frac{1}{3}+70*\frac{2}{3}. Sufficient.

(2) Sum of heights equals to 178 feet 9 inches --> only nominator is given. Not sufficient.

Answer: A.

Hope it helps.

Hi Bunuel,

The fact that confused me is the word tallest in statement 1.

It says "average height of

n/3 [highlight]tallest[/highlight] people in the group is 6 feet 2.5 inches.

Isn't this bit ambiguous? We have no clue how many people to consider in

tallest category?