Question 1017376
Call Mom's and Lee's age NOW, M and L.
Then we can write
M - 6 = 3(L - 6)  and
M = L + 28
Substitute this into the first equation and get
L+28 - 6 = 3(L - 6)
L + 22 = 3L - 18
Add 18 and subtract L from both sides and get
L + 40 = 3L
40 = 2L
L = 20 years old NOW.