Question

A two-digit number is such that the product of the digits is 16. When 54 is subtracted from the number, the digits are interchanged. 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

.

And the number is

Thus, the required number be