Question

In each of the following numbers, replace M by the smallest whole number to make the resulting number divisible by $11$.
(i) $36M2$

Answer 1

Step: Find the value of $M$
Given number: $39M2$
number is divisible by $11$, if the difference of the sum of its digits in odd places from the right side and the sum of digits in even places from the right side is divisible by $11$.​
Here,​
Sum of odd digits = $2+9=11$​
Sum of even digits = $M+3$​
​Difference = $11-(M+3)=8–M$
​Now, since $M$ is a whole number, and we know that $0$ is divisible by $11$,​
Thus, $8-M=0$​
⇒ $M=8$.​
Hence, the value of $M$ is $8$.​