Question

A two-digit number is such that the product of its digits is 8. When 18 is subtracted from the number, the digits interchange their places. Find the number.

Answer 1

Let the tens digit be , then, the unit digits

Therefore, number

And number obtained by interchanging the digits

Then according to question

Or

So the digit can never be negative.

Therefore,

When then the unit digits is

And therefore the number is

Thus, the required number be