Bunuel wrote:
Is the average (arithmetic mean) of 5 different positive integers at least 30?
It's almost always better to express the average in terms of the sum. The question basically asks whether the sum of 5 different positive integers is at least 5*30=150.
(1) Each of the integers is a multiple of 10 --> the least values of these 5 different positive integers are: 10, 20, 30, 40, and 50 --> the sum = 150. Sufficient.
(2) The sum of the 5 integers is 160. Directly answers the question. Sufficient.
Answer: D.
Bunuel... nice way to explain.
However, don't you think statement A and B contradicts each other.
For example, As per statement 1, 5 numbers are multiple of 10;
hence average should be mid number. (In your list 30 is the average)
As per statement 2, The average is 160/5 = 32. Now 32 is not the multiple of 10. By no means we can get 32 as average and 5 numbers multiple of 10
Please explain, am I missing something as this is GMAT prep problem
We are not told that the integers are evenly spaced so it's not necessary that the average is the middle number (in my example, yes, I consider evenly spaced set, but it's just one of the cases). For example the set could be 10, 20, 30, 40, and 60 --> sum=160 --> average=160/5=32.