An old man distributed all the gold coins he had to his two sons into two different numbers such that the difference between the squares of the two numbers is 81 times the difference between the two numbers. How many coins did the old man have?	Choices.
A) 24
B) 26
C) 30
D) 81
E) 40

Rationale: let the number of coins one son got be x and the number of coins another got be y . total = x + y . x ^ 2 - y ^ 2 = 81 ( x - y ) - - > x + y = 81 . answer : d .
Answer: D