ted is 12 years older than juan next year ted will be 3 times as old as juan how old is juan?

Question

I need help i’m not understanding 

Answer 1

Let x = Juan's age

Let x + 12 = Ted's age

x + 1 = Juan's age next year

x + 12 + 1 = x + 13 = Ted's age next year

x + 13 = 3(x + 1)

x + 13 = 3x + 3

10 = 2x

5 years = x