Let a boy’s present age be years and his mother’s present age be four times his age
MATHEMATICS · Single correct · AoPS · Mathematics · Quadratic Equations - Part 2 · Quadratic Equations - Part 2
Problem
Let a boy’s present age be x years and his mother’s present age be four times his age. Three years from now, the product of their ages will be 300. Which one of the following quadratic equations in standard form (equal to 0) correctly represents this information?
(a) 4x2+12x−300=0
(b) 4x2+15x−300=0
(c) 4x2+15x−291=0
(d) 4x2+9x−291=0