Just create the income set with approx values. You will find that the average is way above 40K so you can discount the approximation.

netigen wrote:Just create the income set with approx values. You will find that the average is way above 40K so you can discount the approximation.

HI netigen,

This is the first time i saw this kind of problem...

For statement III, would it be safe to take the closest lower band, if the point is hanging in between? The answer in this case is true. (25+25+25+35+35+35+35+55+60+60+60)/11 = 40.9K.

Would this be the correct way in general to tackle this kind?

Cheers

I was like you verbalattack.

I found it quite close to call in a timed environment. And yes this is the first problem I've seen like this. Keeping taking the GMAT preps! They through tons of new problems at you.

I got this one in my second GMAT Prep exam

You do not have to calculate the average

(25+25+25+35+35+35+35+55+60+60+60)

Note 1: You have already taken the approximations which are lower than the actual numbers.

Now assume that the avg is 40.

find and sum the difference of each number above 40 with 40 for e.g.

55-40 + 3x(60-40) = 75

similarly sum the difference from 40 of all numbers less than 40

3x(40-25)+4x(40-35) = 65

Since, 75 > 65 we know that the average will be > 40

I find this much faster than calculating the avg itself.

I can do most of this without pen and paper.

netigen wrote:Note 1: You have already taken the approximations which are lower than the actual numbers.

Now assume that the avg is 40.

Thanks netigen... looks like GMAT also checks your assumption accuracy :roll: