If m and n are positive integers and m^2 + n^2 = 20, what is the value of m^3 + n^3? Choose the most appropriate option
A) 72
B) 224
C) 320
D) 512
E) 1,600
You need to integers which squared are equal 20.   Which could it be ? Let's start with the first integer:   1^2 = 1   2^2 = 4   3^2 = 9   4^2 = 16   Stop. The integers can't be greater than 4 or we will score above 20.   The second integer need to be picked up the same way.   1^2 = 1   2^2 = 4   3^2 = 9   4^2 = 16   The only pair that matches is 4^2 + 2^2 = 20.   So 4^3 + 2^3 = 72.   72nswer 72.)
<result>A</result>
If m and n are positive integers and m^2 + n^2 = 20, what is the value of m^3 + n^3?