Manuel is 5 years older than Jenny. Jenny is 3/4 as old as Manuel. How old is Manuel?

Let Jenny's age be N

And Manuel's age = N + 5

So we have

3/4 (N + 5)  = N  simplify

(3/4)N + 15/4  = N    subtract (3/4)N from both sides

15//4 = (1/4)N    multiply both sides by 4

15 = N 

And  Manue's age  is 15 + 5 = 20