Multiple choice

Jagdish and Chetan, who live in the same town, are going separately to Amritsar. Jagdish takes the bus at 5:00 am in the morning and the bus travels at 50 kmph. Chetan takes the 7:00 am super fast bus, that travels at a speed of 70 kmph. At what time will Chetan's bus be 20 km ahead of Jagdish's bus?

  1. 12:10 pm

  2. 12:40 pm

  3. 1:00 pm

  4. 1:20 pm

  5. 2:00 pm
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Jagdish distance at time t: 50(t-5). Chetan distance at time t: 70(t-7). We want 70(t-7) = 50(t-5) + 20. 70t - 490 = 50t - 250 + 20. 20t = 260. t = 13 (1:00 pm).

AI explanation

Jagdish travels for 2 hours before Chetan starts, covering 100 km at 50 kmph, so Chetan must close this gap and pull ahead by 20 km, meaning a relative distance of 120 km. The relative speed method for same direction movement gives 70 kmph minus 50 kmph, which equals 20 kmph. Using the formula time equals distance divided by speed, the time needed is 120 divided by 20, which is 6 hours. Adding 6 hours to Chetan's 7:00 am start time yields 1:00 pm, so the correct answer is 1:00 pm.

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