Q30.
Yesterday it took a certain plane 3 hours to fly from City A to
City B at an average speed of 400 miles per hour. Today the
same plane flew from City A to City B along the same route at
an average speed of 450 miles per hour. How many more
yesterday than it took today?
A. 10
B. 15
C. 20
D. 25
E. 30
看不懂這題在問什麼?也兜不出答案