Jon treated his sister to lunch while visiting her in Silvergrove. Their lunch cost $75, and the sales tax in Silvergrove is 4%. If Jon left a 20% tip on the $75, how much in total did he pay?

(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

a

explanation: