You first need to find a weighted average call time, since they give you average call volume for each day and also the total number of minutes for each day. They then give a scenario where calls that don't require a transfer to someone else only take a certain time, so you must figure out what the average for the rest of the calls must be. You then need to use that info to solve some problem. it got a little tricky and did require basic algebra. I highly recommend doing a lot of practice GMAT questions to prepare.