Todd is three years younger than his brother Gerardo. In seven years, the sum of their ages will be thirty-nine. How old are they now?

4 answers

T + 3 = G

T + 7 + G + 7 = 39 ... T + G = 25

solve the system of equations
... substitution looks like a good method
can you explain a lil more please I don't understand it.
This is like process map 5d
18 21 = 39 in 7 years
t g
18 - 7 = 11=t
21-7 = 14=g