The weight limit on an elevator is 2500 pounds. assume that the average weight of a man is 190 pounds and the average weight of a woman is 125 pounds. if there are 3 women on the elevator already, what is the maximum number of men that can get on?

(n^3 - n)

= n(n-1)(n+1)

since it is divisible by 3 and 2 ,because it is a multiple 3 consecutive number

if, n-1 is odd then n+1 is also odd, then it is a multiple of 9

but if, n-1 is even then n+1 is also even, then it is a multiple of 4

so, largest multiple = max(9*2, 4*3) = max(18, 12) = 18

goog may have it for you