Question

Q. The unit’s digit in the operation
$({57}^{61}+6^{49}+3^{65})$ is

• A. 6
• B. 0.0
• C. 3
• D. 8
• E. 7

Answer 1

The correct option is D 8

$7^4$ gives 1 in units place
$7^{61}=7^{{15}^4}\times 7^1$
Which gives 7,
Every power of 6 will give unit digit as 6.
$3^4$ gives 1 in units place
$3^{65}=3^{{21}^3}\times 3^2$
Which gives 9 in units place
So $7\times 6\times 9=378$