Mary is now three times as old as her daughter. Four years ago the products of their age was 40 .calculate their present years

Answer 1

now:
daughter ---- x years
Mary -------- 3x years

4 years ago:
daughter : x-4
Mary : 3x-4

(x-4)(3x-4) = 40
3x^2 -16x + 16 = 40
3x^2 - 16x - 24 = 0
I was expecting it to factor, hoping for whole number solution, but ....

x = (16 ± √544)/6
= 6.55 or a negative

check:
if the daughter is appr 6.55
then Mary is 19.65 years old
Four years ago, Mary was 15.65 and the daughter was 2.55 , and 15.65(2.55) = 39.9 or
appr 40

The math works out, but Mary was 13 when the daughter was born. Somebody should be in jail.