X and
Y are positive integers, neither of which is divisible by 10. Their product is 100,000.
What is X + Y ?
The factors of 100,000 are 2
^{5} and 5
^{5}. As the factors of 10 are 2 and 5, in order that both X and Y are not divisible by 10, X and Y each must be solely composed of one of the two factors; that is, e.g., X = 2
^{5} (= 32) and Y = 5
^{5 }(= 3125). The sum of the two numbers is
3157 (= 32 + 3125).

Posted by Dej Mar
on 20080621 01:38:41 