GMATPASSION wrote:

Three people each took 5 tests. If the ranges of their scores in the 5 practice tests were 17, 28 and 35, what is the minimum possible range in scores of the three test-takers?

A. 17

B. 28

C. 35

D. 45

E. 80

Min possible range. That means the lowest possible difference in total 15 values.

0 0 0 0 17

0 0 0 0 28

0 0 0 0 35

Minimum possible range is 35. Oh got the trick.

But my question is If I am thrown a question like this in the test I might panic & try many different kind of values. Is there a particular strategy or pattern for this type of questions.

Try to look at it as overlapping sets problem:

# of people in group A is 17;

# of people in group B is 28;

# of people in group C is 35;

What is the minimum # of total people possible in all 3 groups? Clearly if two smaller groups A and B are subsets of bigger group C (so if all people who are in A are also in C and all people who are in B are also in C), then total # of people in all 3 groups will be 35. Minimum # of total people can not possibly be less than 35 since there are already 35 people in group C.

Answer: C.

Hope it's clear.

P.S. Notice that max range for the original question is not limited when the max # of people in all 3 groups for revised question is 17+28+35 (in case there is 0 overlap between the 3 groups).

Sorry Bunuel but I am still not convinced by this explanation..... for example if you have the following votes:

You would have range 35 for third group, but the range of all three groups would be 39-1= 38 > 35 ?