GRAHAM WALKED TO SCHOOL AT AN AVERAGE SPEED OF 3 MILES AN HOUR AND JOGGED BACK ALONG THE SAME ROUTE AT 5 MILES AN HOUR.IF HIS TOTAL TRAVELLING TIME WAS 1 HOUR,what was the total number of miles in the round trip
A,3 B,3+1/8 C,3+3/4 D,4 E,5