Question

What is the unit digit of the number $5^{25}$ × $6^{36}$?

• A. 5
• B. 0
• C. 6
• D. 1

Answer 1

The correct option is B

0

$5^1$​ = 5

$5^2$ = 25

$5^3$= 125

$5^4$ = 625

So, 5 raised to the power of any positive exponent will have 5 as the last digit .

$6^1$ = 6

$6^2$ = 36

$6^3$ = 216

So, 6 raised to the power of any positive exponent will have 6 as the last digit.

Hence, the unit digit of the product of _ _ _ 5 and _ _ _ 6 is 0 .

_ _ _ 5

× _ _ _ 6

__________
0