Question

What is the value of $x$ such that $71x$ is divisible by $7$?

• A. $3$
• B. $2$
• C. $1$
• D. $4$

Answer 1

The correct option is D $4$

We know the divisibility rule for $7$:
Choose the last digit of the number, multiply it by $2$, and subtract the product from the rest of the number and the answer is $0$ or divisible by $7$.
Here, $714$ is divisible by $7$.
$714$ when we multiply with $2$ the last digit become, $718$.

Then subtract the last digit number $8$ from $71$,

we get $71-8=63$ is divisible by $7$.
So, option D is correct.