Two cars X and Y start at the same point and travel towards a point P which is 150km away. If the average speed of Y is 60km per hour and x arrives at P 25 minutes earlier than Y. What is the average speed of X?
-
A.
51(frac{3}{7})km per hour -
B.
72km per hour -
C.
37(frac{1}{2}) km per hour -
D.
66km per hour -
E.
75km per hour
Correct Answer: Option B
Explanation
Distance travelled by both x and y = 150 km.
Speed of y = 60km per hour, Time = (frac{dist.}{Speed})
Time spent by y = (frac{150}{60})
= 2(frac{3}{6})hrs
= (frac{1}{2}) hrs
if x arrived at p 25 minutes earlier than y, then time spent by x = 2 hour 5 mins
= 125 mins
x average speed = (frac{150}{125}) x (frac{60}{1})
= (frac{9000}{125})
= 72 kmhr