CAT 2020 Slot 1 QA Q19 Time, Speed & Distance

Question 19 of the Quantitative Ability (QA) section, CAT 2020 Slot 1, with CAT's official answer and a worked solution.

Leaving home at the same time, Amal reaches office at 10:15 am if he travels at 8kmph, and at 9:40 am if he travels at 15kmph. Leaving home at 9:10 am, at what speed, in kmph, must he travel so as to reach office exactly at 10:00 am?
  1. A
    12
  2. B
    11
  3. C
    13
  4. D
    14

Answer: (A) 12 Time, Speed & Distance MCQ

Solution

  1. The two arrival times differ by 35 min: \(\frac{d}{8}-\frac{d}{15} = \frac{35}{60} \Rightarrow \frac{7d}{120} = \frac{7}{12} \Rightarrow d=10\) km.
  2. From 9:10 to 10:00 is 50 min, so speed \(= \frac{10}{50/60} = 12\) km/h.

Same concept in other years

See every question on Late at one speed, early at another: solve for distance.

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