Question

When you reverse the digits in a certain two-digit number, you decrease its value by 18. What is the number is the sum of its digits is 4?

Answer 1

It is `13`

Explanation:

Let `x` and `(4-x)` represent the unit and tens digits of this certain two-digit number

#10*(4-x)+x=10*x+(4-x)-18=> 40-10x+x=10x+4-x-18=> 40+18-4=10x+10x-2x=> 54=18x=>x=3#

Hence the unit digit is 3 the tens unit is 1.So the number is 13.

Check :`31-13=18`