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?
- 51\(\frac{3}{7}\)km per hour
-
72km per hour
- 37\(\frac{1}{2}\) km per hour
- 66km per hour
- 75km per hour
The correct answer is: 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 km\hr