Two points P and Q are 210 km apart. Train A leaves P for Q at 50 km/h at 10:00 AM. Train B leaves Q for P at 70 km/h at 11:00 AM. At what time will they pass each other? MCQ with Answer and Explanation
Two points P and Q are 210 km apart. Train A leaves P for Q at 50 km/h at 10:00 AM. Train B leaves Q for P at 70 km/h at 11:00 AM. At what time will they pass each other?
A. 1:00 PM
B. 12:20 PM
C. 12:00 PM
D. 12:40 PM
Answer: Option B
Solution (By JKSSB Mock Tests)
By 11:00 AM, Train A covers 50 km * 1 hour = 50 km. Remaining distance = 210 - 50 = 160 km. Relative speed = 50 + 70 = 120 km/h. Time to meet after 11:00 AM = 160 / 120 = 4/3 hours = 1 hour 20 minutes. Meeting time = 11:00 AM + 1 hour 20 minutes = 12:20 PM.
Two sprinters race on a 200-meter straight track. The ratio of their speeds is 4 : 5. When the winner crosses the finish line, how far away from the tape is the slower sprinter?
Explanation:
The faster sprinter covers 5 parts = 200 meters, so 1 part = 40 meters. In that same timeframe, the slower sprinter covers 4 parts = 4 * 40 = 160 meters. Distance remaining for the slower sprinter = 200 - 160 = 40 meters.
Explanation:
New speed = 6/7 of usual speed => New time = 7/6 of usual time. Difference = 1/6 of usual time = 10 minutes. Usual time = 10 * 6 = 60 minutes.
A person covers a distance in 40 minutes if he drives at an average speed of 45 km/h. At what speed must he drive to reduce the time of journey to 30 minutes?
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