If M is Monica's age, then Chandler's age is M+5 years. Fifteen years ago (M-15) + ((M+5) - 15) = 45 2M - 25 = 45 2M = 45 + 25 = 70 M = 70/2 = 35. ANSWER. Monica is 35 years old; Chandler is 35+5 = 40 years old.