Question

Find the remainder when $9^{178}$ is divided by 4.

• A. 1
• B. 2
• C. 3

Answer 1

The correct option is A 1

$9^{178}$ can be written as $(8+1{)}^{178}=(2\times 4+1{)}^{178}.$
So remainder will be $1^{178}=1.$
Infact any number of the form $9^x$ will leave a remainder 1 when divided by 4.