Dustin complained 3/8 of a homework assignment that has 24 problems. Kelsey completed 4/15 of a homework assignment that has 30 problems. Who has completed more problems?

Dustin has completed more problems.

You can first use the 2 factors of 24, which are 3 and 8. To make it so you can compare the amount of problems completed with total amount, you need to multiple 8 x 3 and 3 x 3. This will turn 3/8 into 9/24, meaning that dustin has completed 9 problems. You can first use the 2 factors of 30, which are 2 and 15. Once again, to make it so you can compare the amount of problems completed with total amount, you need to multiple 2 x 15 and 2 x 4. This will turn 4/15 into 8/30, meaning that kelsey has completed 8 problems.