Question

The sum of the digits of a two-digit number is 7. the new number obtained when the digits are reversed is 27 less than the original number. find the original number

Answer 1

We can figure this out by finding all the combinations:
0 + 7 = 7 (07)
1 + 6 = 7 (16)
2 + 5 = 7 (25)
3 + 4 = 7 (34)
4 + 3 = 7 (43)
5 + 2 = 7 (52)
6 + 1 = 7 (61)
7 + 0 = 7 (70)

Obviously 70 can't be our number, as it would be a one digit number,

Since we're going down in value ( 27 less ) our original number will be a larger number.

52 reversed is 25 which is 27 less than 52.

Our original number is 52 here.