Pls explain

[Nycgrl]

The surface area of a square tabletop was changed so that one of the dimensions was reduced by 1 inch and the other dimension was increased by 2 inches. What was the surface area before these changes were made?
(1) After the changes were made, the surface area was 70 square inches.
(2) There was a 25 percent increase in one of the dimensions.

[atlantic]

Let 'L' be the original side length of the square tabletop.

Changed dimensions are L-1 and L+2

(1) says that (L-1)(L+2)=70, so you can calculate L, SUFF

(2) says that L+2=1,25L, so you can calculate L, SUFF

Answer D.