The sum of the digits of a two digit number is 7. When 27 is subtracted from the number the digits of the number will reverse.
What is the original number?
52
Given sum of the digits is 7. So, if the digit in the unit’s place is x ,then the ten’s place digit will be 7 – x.
Then the number will be 10(7 – x) + x. After reversing the digits the number will be 10x + (7 – x).
10(7 – x) + x – 27 = 10x + (7 – x)
70 -10x + x – 27 = 10x + 7 – x
43 – 9x = 9x + 7
43 – 7 = 9x + 9x
18x = 36
x = 36 ÷ 18 = 2
∴ The number is 52.