1 70%
Toilet rolls come in packs of 4 and 9.
The 4-pack is priced at £2.25.
The 9-pack is priced at £4.50.
By calculating the price per roll, determine which pack is better value.
Show your working.

what does 1 and 70% mean in this question

(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