There are numerous puzzles about ages, and most of them can be solved with elementary algebra, though the hassle of tracking forward and backward into time can sometimes be confusing.
2) My friend and his granddaughter*
A friend told me: 3 years ago, I was thrice as old as my granddaughter. 8 years before I that, that is, 8 years before I was three times as old, I was four times as old.
How old is my friend?
You can check your solution here