Rob spent 25% more time on his project than he had planned. He spent an extra "h" hours on it.

Which of the following expressions could represent the number of hours Rob actually spent on the project:

A: 5 h

B: (h/25) 1.25

C: 1.25 h

D: 4 h

E: (1+ 25/100) h

In the solution they set up the answer by starting with h/.25

Why would we need to calculate what 25% of "h" which is the extra time spent? It makes no sense to determine what 25% of the extra time is since "h" IS the extra time spent.

Any help would be greatly appreciated since I'm at a loss here.