Is the average (arithmetic mean) of 5 different positive integers at

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.

Hope it's clear.

why cannot we consider 0,10,20,30,40? Isn't 0 taken as both positive and negative?

One question: is zero not considered as a multiple of any number?

Yes, 0 is a multiple of every integer.

Why are we not considering 1 as multiple of 10?

1 is a factor (divisor) of 10, not a multiple of 10.

A more detailed explanation can be found here:
https://www.youtube.com/watch?v=aioddTGJ-KU

Average = (SUM of terms)/(# of terms)

Since we're told what the average is, the real question becomes, "What is the sum of the terms?" That's the information we need to know in order to answer the question.

Statement (1) First, a quick point - zero is an integer, and zero is also a multiple of 10 (10*0 = 0), but since zero is not a POSITIVE integer (it's neither negative nor positive), it can't one of the 5 numbers.

The smallest possible numbers, therefore, are 10, 20, 30, 40, 50. We can (easily) find the sum, so statement (1) gives us sufficient info to answer the question.

Statement (2) clearly tells us exactly what we need to know, as well.

Answer D

(1) Since we're told we have 5 different integers, 10 + 20 + 30 + 40 + 50 = 150

150 / 5 = 30. The average will be at least 30. SUFFICIENT.

(2) Answers our question; SUFFICIENT.

Answer is D.

0 is not a positive number. So we cannot take zero. Also, any combination of numbers works because the average should be at least 30. It can be more than 30 also.

Bunuel

Please help me understand. I might have misunderstood the English but for Statement 1 - why can't all the 5 integers be 10? What in the sentence tells me that all 5 are unique?

question: Is the average (arithmetic mean) of 5 different positive integers at least 30?


5 different

oh wow... amateur hour for me... Thanks for the fast response AnkithaSrinivas

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