CAT 1997 — QA Question 1
Answer the next 3 questions based on the following information.
A certain race is made up of three stretches: A, B and C, each 2 km long, and to be covered by a certain mode of transport. The following table gives these modes of transport for the stretches, and the minimum and maximum possible speeds (in km/hr) over these stretches. The speed over a particular stretch is assumed to be constant. The previous record for the race is 10 min.
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Anshuman travels at minimum speed by car over A and completes stretch B at the fastest speed. At what speed should he cover stretch C in order to break the previous record?
Answer & solution
- A
Maximum speed for C
- B
Minimum speed for C
This is not possible
- D
None of these
If he travels at minimum speed over stretch A (i.e. 40 km/hr), the total time taken to cover this stretch hr = 3 min.
If he then travels at the fastest speed over stretch B (i.e. 50 km/hr), the total time taken to cover this stretch = = 2.4 min.
Thus, total time taken over the first two stretches = (3 + 2.4) = 5.4 min.
In order to break the previous record he will have to cover the third stretch in (10 – 5.4) = 4.6 min. To do this he will have to cover the third stretch at = 0.434 km per minute or 26.08 km/hr. But the maximum speed over the stretch C is 20 km/hr. Hence, it is not possible for C to break the previous record.