Answer 1

Suppose, the units place digit of the two digit number is y and the tens place digit is x.
∴ the number is 10x + y
∴ the number obtained by reversing the digits is 10y + x
∴ from the given conditions, 

`(10x+y)+(10y+x)=121` 

∴ 11x+11y=121                                ∴ x+y=11 .............(I)

Also, x=y+7                                      ∴ x-y=7 ................(II) 

∴ Adding (I) and (II), `2x=18       x=9`

∴ from (I) `a+y=11`     `    y=2` 

∴ the two digit number is 29.