arithmetic - the ages of two persons differ by 12 years if 4 years ago the elder one be 3 times as old as the younger one find their present ages in years - skillgun

Solution: Let the age of the younger person be x years. Then, age of the elder person = (x + 12) years.
.'. 3(x - 4) = (x + 12 - 4) => 2x = 20 => x = 10.
hence the present ages are 10 years and 22 years.