Question

Find the numbers whose square will end with digit $1$.

• A. $(49{)}^2,(19{)}^2$
• B. $(18{)}^2,(48{)}^2$
• C. $(15{)}^2,(25{)}^2$
• D. $(24{)}^2,(42{)}^2$

Answer 1

The correct option is A $(49{)}^2,(19{)}^2$

The numbers which will have $1$ at their unit place in their squares are the numbers ends with $1$ or $9$

Because $1\times 1$ $=$ $1$ and $9\times 9=81$

Hence, Option A is correct answer.