Question

What is the missing digit which makes the number $56$_$8$ exactly divisible by $3$?

• A. $1$
• B. $2$
• C. $3$
• D. $4$

Answer 1

Answer: (B)

$2$

We know the divisibility rule for $3$:
If the sum of the digits of a number is divisible by $3$, then the number is also divisible by $3$.
So, $5+6+x+8=19+x$ is divisible by $3$

$⟹19+x=0,3,6,9,12,15,18,21,.....$

$⟹x+19=21$

$⟹x=2$

So, the missing digit is $2$

So, option B is correct.