Richard and Teo have a combination age of 31. Richard is 4 years older than twice Teo's age. How old are richard and Teo?

You need to find two numbers that add up to 31, and one is 4 years older than twice Teo's age. 

9*2= 18+4= 22

22+9= 31

Teo is 9 years old, and Richard is 22.

I hope this helps!
~kaikers