The sum of two numbers is 30. Their difference is 6. What are the numbers?

6 and 24

12 and 18

10 and 20

8 and 14

Okay lets start by getting rid of the ones that don't have a difference of 6. We are now left with '12 and 18' and '6 and 14'. If we take a look we can see that '6 and 14' add up to 20. So it is clear that only '12 and 18' add up to 30 and have a difference of 6.