Answer:
The numbers less that 40 which have sum of digits 8 are 17, 26, 35.
Only one of those that has a factor of 7. And that is 35.
So you are 35.
Second way:
The numbers less that 40 which have a factor of 7 are 7,14,21,28,35
Only one of those which has sum of digits as 8. And that is 35.
So you are 35.
Explanation: