D is correct for this problem
Time taken by a regular bus to reach its destination = 3 1/4 hours
= 13/4 hours
Time taken by the express bus to make the same trip = 2 1/2 hours
= 5/2 hours
Time that can be saved by taking the express bus = (13/4) - (5/2) hours
= (13 - 10)/4 hours
= 3/4 hours
So 3/4 hours can be saved by taking the express bus rather than the regular bus. The correct option among all the options given in the question is option "C". I hope the procedure is simple enough for you to understand.
Remember you can do anything to an equation as long as you do it to both sides
and when multiply by negative, flip sign
8+h>2+3h
minus h both sides
8+h-h>2+3h-h
8+0>2+2h
8>2+2h
minus 2 both sides
8-2>2-2+2h
6>0+2h
6>2h
divide by 2 both sides
6/2>2h/2
3>1h
3>h
first opotin
12 because the rest of the numbers are all similar except 12
