Question

$5\ast 25$ is a square of $75.$Which digit should replace $\ast$?

• A. $1$
• B. $6$
• C. $3$
• D. $4$

Answer 1

The correct option is B $6$

Multiply ten's digit with its next number.
$7\times (7+1)=7\times 8=56---\left(1\right)$
Find the square of unit's digit: $5$
$5^2=25$ ----(2)
Combining (1) and (2), we get
$5625=75\times 75$
So, $6$ is the missing number.