Correct Answer:
Option A - Let the two digit number (pq) = 10x + y
Then, qp = 10y + x
According to the question,
pq – qp
= 10x + y – (10y + x)
= 10x + y – 10y – x
= 9x – 9y
= 9 (x – y)
Hence pq – qp will be completely divisible by 9.
A. Let the two digit number (pq) = 10x + y
Then, qp = 10y + x
According to the question,
pq – qp
= 10x + y – (10y + x)
= 10x + y – 10y – x
= 9x – 9y
= 9 (x – y)
Hence pq – qp will be completely divisible by 9.