Question

On dividing a positive integer n by 9, we get 7 as remainder. What will be the remainder if 3n-9 is divided by 9? Need a well explained answer!

Answer 1

if  n by 9 is =7 (remainder)
so, 3n - 9 =[(3*n)-9]
                  n= 9+7=16              i.e. n=16
                   [(3*16)-9]
                   [(48)-9]
                   [48-9]=39
so,3n-9=39

Answer 2

n÷9=7
n=9×7
=63
if n is 63 then
3n-9÷9=(3×63-9)÷9
=(189-9)÷9
=180÷9
=20 and 0 remainder