If six is placed at the end of a two digit number the result is 294 greater than the number, what was the number?

If 6 is placed at the right end of AB, so the number is AB6. 
the value of the three-digit number formed is 294 more than AB, means that if AB6 - 294 = AB 

AB 6 
- 2 9 4 
AB 

6 - 4 = B = 2 

If B = 2, then the tens digit is 2 - 9 (which can't be) so 12 - 9 = 3 = A 

A = 3, and B = 2 

check: 326 - 294 = 32