Question

When the positive integer N is divided by $5$, the remainder is $3$. What is the remainder when $20$N is divided by $25$?

Answer 1

Take any number which is of the form $N=5x+3$ where $x$ is any positive Integer

When $N$ is Multiplied by $20$ it will become $=100x+60=100x+50+10$

Clearly when this is divided by $25$ the Quotient will be $=4x+2$ and remainder will be $10$ as it is not divisible by $25$.

Therefore Answer is $10$