Question

Find the largest factor of 2520 that is not divisible by 6.

Answer 1

315

Answer 2

how do u calculate it ?

Answer 3

well the prime factorization of 2520 is
2^3 x 3^2 x 5 x 7
any factor of 2520 that is divisible by 6 contains at least one 2 and at least one 3 in its prime factorization.
so remove factors so that no 2's remain or no 3's remain
if we remove all the 3s, we divide the number by 3^2 = 9.
but if we remove all the 2s, we divide the number by 2^3 = 8
since 8 is less than 9
the last factor 2520/8 = 315

Answer 4

How did i calculate ....
2 x 2 x2 x 3 x 3 x5 x 7
the remainder value at first occurance of 3 is 315 which is not divisible by 6
first 3 occurance of 2 ... remainder values are divisible by 6
does it make sense