25 Oct '07 17:141 edit

I have 3 numbers, lets call them a, b and c. I am surprised to see that one of the pairs is such that the difference between the two numbers is exactly equal to the difference between their squares.

ie a-b = a^2-b^2

when I look at the other pairs I find that in one pair the difference between their squares is twice their difference and in the final pair the difference between their squares is thrice their difference.

What is the sum of a, b and c?

(The problem is easy ... your solution must be concise!)

ie a-b = a^2-b^2

when I look at the other pairs I find that in one pair the difference between their squares is twice their difference and in the final pair the difference between their squares is thrice their difference.

What is the sum of a, b and c?

(The problem is easy ... your solution must be concise!)