marcodonzelli wrote:

A and B are in a line to purchase tickets. How many people are in the line?

(1) There are 15 people behind A and 15 people in front of B.

(2) There are 5 people between A and B.

how to approach this kind of problems?

(1) We can conclude that the line looks like:

[15 people] A..........B [15 people], OR

......A [15 people] B........

Insufficient to calculate the total number of people in line (as we don't have any information on the dotted portion)

(2) The line looks like

.........A [5 people] B........

Insufficient

Combining (1) and (2), the line looks like:

[15 people] A [5 people] B [15 people]

or a total of 37

The answer is (C)

_________________

My GMAT debrief