alleryConvert 72 km/h to m/s.
- $25$ m/s
- $20$ m/s
- $15$ m/s
- $10$ m/s
Show answer and solution
Correct answer: B. $20$ m/s
km/h to m/s: multiply by 5/18. 72 × 5/18 = 360/18 = 20 m/s.
GMAT Time, Speed and Distance — practice questions
Explore 17 free Time, Speed and Distance questions in GMAT Quantitative Reasoning. Open each question or exercise to read its content, reference answers and available explanation.
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Showing questions 1–17 of 17.
Convert 72 km/h to m/s.Read the answer and worked solution →A car covers the first 60 km at 30 km/h and the next 60 km at 60 km/h. What is the average speed for the whole journey?Read the answer and worked solution →A bus travels equal distances at 40 km/h and 60 km/h. What is the average speed for the whole journey?Read the answer and worked solution →A 150-metre train at 54 km/h crosses a stationary pole. How long does it take?Read the answer and worked solution →A 200-metre train at 36 km/h crosses a 100-metre platform. How long does it take?Read the answer and worked solution →A boat covers 24 km downstream in 2 hours and the same 24 km upstream in 3 hours. What is the speed of the stream?Read the answer and worked solution →A car that usually takes 6 hours for a trip now takes 4 hours due to a higher speed. By what factor did the speed increase?Read the answer and worked solution →Pipe A fills a tank in 8 hours; Pipe B fills it in 12 hours. How long do both pipes take together?Read the answer and worked solution →A driver increases his speed by 25%. By what percentage does the journey time decrease (for the same distance)?Read the answer and worked solution →For a fixed distance, if the speed is increased then the time taken:Read the answer and worked solution →A journey takes 120 km at a steady 60 km per hour. The time taken is:Read the answer and worked solution →Zaheeda doubles her speed on the same route. The time she takes:Read the answer and worked solution →A car covers 300 km at 50 km per hour. At 75 km per hour the same trip would take:Read the answer and worked solution →A train 150 m long runs at 54 km per hour. The time it takes to pass a pole is:Read the answer and worked solution →A train 200 m long crosses a 100 m platform at 36 km per hour. It takes:Read the answer and worked solution →A man travels equal distances at 40 km per hour and at 60 km per hour. His average speed is:Read the answer and worked solution →A man covers a distance in 6 hours at 40 km per hour. To cover it in 4 hours he must travel at:Read the answer and worked solution →
Worked practice questions
A car covers the first 60 km at 30 km/h and the next 60 km at 60 km/h. What is the average speed for the whole journey?
- $40$ km/h
- $45$ km/h
- $48$ km/h
- $50$ km/h
Show answer and solution
Correct answer: A. $40$ km/h
Total distance = 120 km.
Time on first leg = 60/30 = 2 h.
Time on second leg = 60/60 = 1 h. Total time = 3 h.
Average speed = 120/3 = 40 km/h.
(Simple average 45 km/h is the trap.)
A bus travels equal distances at 40 km/h and 60 km/h. What is the average speed for the whole journey?
- $50$ km/h
- $45$ km/h
- $48$ km/h
- $52$ km/h
Show answer and solution
Correct answer: C. $48$ km/h
Equal-distance legs use harmonic mean: 2ab/(a+b) = 2 × 40 × 60 / (40+60) = 4800/100 = 48 km/h.
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