Which of the following statement(s) is/are wrong?

1.A man runs at a speed of 20 km/hr and covers a distance of 400 m. The time taken by the man to cover 400 m is 8 minutes.

2.A person covers a certain distance at x km/hr and an equal distance at y km/hr. The average speed during the whole journey is 2xy/(x+y) km/hr.

3.A Cyclist covers a distance of 750 m in 2½ minutes. The speed of the cyclist is 18 km/hr.

4.A speed of x km/hr is equal to 5x/18 m/sec.

A1 only ✓ Correct

B1 & 2 only

C1 & 3 only

D2, 3 & 4 only

Correct answer: (A) 1 only

Explanation

Only statement 1 is wrong.

Statement 1: time = 0.4/20 = 0.02 hr = 1.2 min, not 8 min.

Statement 2: equal-distance average speed = 2xy/(x+y) is correct.

Statement 3: 0.75/(2.5/60) = 18 km/hr is correct.

Statement 4: x km/hr = 5x/18 m/sec is correct.

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