Question

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

• A. $3$
• B. $4$
• C. $5$
• D. $6$

Answer 1

The correct option is D $6$

Step 1 :Multiply ten's digit with its next number.
$2\times (2+1)=2\times 3=6---\left(1\right)$
Step 2 : Find the square of unit's digit: 5
$5^2=25----\left(2\right)$
Combining (1) and (2), we get
$25\times 25=625$
$6$ is the missing number.