Multiple choice

A is 15 km ahead of B. A and B’s speeds are 3 km/hr and 8 km/h. In what time will A cross B.

  1. 5 hr.

  2. 3 hr.

  3. 4 hr.

  4. 6 hr.

  5. None of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A is ahead by 15 km. Since A is slower (3 km/h) than B (8 km/h), B will catch A, not the other way around. Relative speed = 8-3 = 5 km/h (B catching A). Time = 15/5 = 3 hours. The question asks when 'A crosses B' which incorrectly implies A is faster, but the calculation gives 3 hours. Option B is numerically correct for the catch-up time.

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