A truck driver has to cover a total distance of 260 km in 4 hours. He drives at a speed of 56 km/h for the first 75 minutes, and
the next 90 km at a speed of 60 km/h. At what speed (in km/h) must he drive the remaining distance in order to complete the
journey in 4 hours?
This questions was previously asked in
SSC MTS 2nd Nov 2021 Shift-1
Explanation:
- The total distance to cover is 260 km in 4 hours.
- First Leg: The driver covers a distance at 56 km/h for 75 minutes.
- Distance = Speed × Time = 56 km/h × (75/60) h = 70 km.
- Second Leg: The next 90 km is at 60 km/h.
- Time taken = Distance ÷ Speed = 90 km ÷ 60 km/h = 1.5 hours.
- Total Time for First and Second Leg:
- = (75/60) hours + 1.5 hours
- = 1.25 hours + 1.5 hours
- = 2.75 hours.
- Remaining Time:
- Total time allowed is 4 hours, so remaining time is 4 - 2.75 = 1.25 hours.
- Remaining Distance:
- Total distance is 260 km. He already covered 70 km + 90 km = 160 km.
- Remaining distance = 260 km - 160 km = 100 km.
- Required Speed for Remaining Distance:
- Speed = Distance ÷ Time = 100 km ÷ 1.25 hours = 80 km/h.
Correct Answer: Option 3 - 80 km/h
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By: santosh