Question 720107
Let 'm' be the age of mother and 'k' be the age of the kid.

Given :  m = 2k + 12 -------eq.1

After 8 years ,
m' = m + 8 , k' = k +8
m' = 3k' - 20  = 3(k + 8) - 20 = 3k + 4 = m + 8

m = 3k - 4 ------------eq.2

put eq.2 in eq.1

3k - 4 = 2k + 12
k = 16
m = 44