NECO 2004 Mathematics · Question 6

A car travels at an average speed of 75km/h. Find its speed in metres per second.

Options

A.270m/s
B.208m/s
C.27.0m/s
D.20.8m/s
E.2.08m/s

Answer: D. 20.8m/s

Explanation written with AI and checked against the answer key

Analyze the question: We need to convert 75 km/h into m/s.

Concept:

1 km = 1000 m
1 hour = 3600 seconds

So to convert km/h to m/s, multiply by 1000/3600 = 5/18.

Solution:

Speed = 75 km/h

= 75 × 1000 m / 3600 s

= 75000 / 3600 m/s

= 20.83 m/s

Using the shortcut: 75 × 5/18 = 375/18 = 20.83 m/s ≈ 20.8 m/s

Answer: Option D (20.8 m/s).

Tip: To convert km/h to m/s, multiply by 5/18. To go from m/s to km/h, multiply by 18/5. You can also sanity-check: 36 km/h is 10 m/s, so 75 km/h should be a little over 20 m/s. That immediately rules out options A, B, C, and E.

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