Which could be the area of one lace on the rectangular prismy select three options,

24 square inches
28 square inches
36 square inches
54 square inches
63 square inches

I think best answer would be

Since it takes her 2 1/2 miles to get to the aquarium from her hotel, you need to subtract the various distances from  this value in order to find how long it took Clara to walk the rest of the way to the aquarium. 

2 1/2 - (1/4+1 3/4)= 2 1/2 - 2= 1/2

Clara must walk 1/2 a mile to get the rest of the way to the aquarium.