kostyan5 wrote:

This problem doesn't make any sense because it says "$6.00 for one kind of D and one kind of C". Later on, it says that the average price of D and C is .35.

Agree that the wording is deceiving, but have another read.

It says 'one kind' of donut. E.g. you buy five chocolate donuts, you have bought

one kind of donut, even though you have bought five.

This is actually a GMATPrep problem.

The proper wording is "At the bakery, Lew spent a total of $6.00 for one kind of cupcake and one kind of doughnut. How many doughnuts did he buy?"

We never can answer a question from the stem along, hence if we read this to mean 'one' donut was bought (which directly answers the question), then we know we have made a mistake.