A woman is 4 times as old as her son. 9 years ago, the sum of their ages was 42. Find their present ages

36 years

Step-by-step explanation:

Let

Daughter = x

Mother = 3*x = 3x

6years ago? Daughter = x-6

Mother = 3x-6

Sum of ages at this time = (x-6) + (3x-6) = 36

x - 6 + 3x - 6 = 36

4x + (-12) = 36

4x = 36 + 12

4x = 48

x = 48/4; 12 years old.

Mother = 12*3 = 36 years old.

Check. 12-6 = 6;

36-6=30

30+6=36 years.