Need help with linear equations with one variable

This is the task:

Tim's mother is three times older than Tim. In 14 years, she'll be 2 times older than him. How old are they now?

This text needs to be converted into a linear equoation with one variable and I am supposed to calculate how old is Tim and how old is Tim's mother. I can't seem to get it right. I've tried many different combinations, but I can't.

Please help me, cause I need the answer and I need to know how to solve these types of problems.

Thanks in advance.