The ages of Tosan and Isa differ by 6 and the product of their ages is 187. Write their ages in the form (x, y), where x > y.
A. (12, 6) B. (23, 17) C. (17, 11) D. (18, 12)
Correct Answer: C
Explanation
x - y = 6.......(i) xy = 187.......(ii) From equation (i), x(6 + y) sub. for x in equation (ii) = y(6 + y) = 187 y2 + 6y = 187 y2 + 6y - 187 = 0 (y + 17)(y - 11) = 0 y = -17 or y = 11 y cannot be negative, y = 11 Sub. for y in equation(i) = x - 11 = 16 x = 6 + 11 = 17 ∴(x, y) = (17, 11)
