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CAT 1999 — QA Question 6

VariationEasy

The speed of a railway engine is 42 kmph when no compartment is attached, and the reduction in speed is directly proportional to the square root of the number of compartments attached. If the speed of the train carried by this engine is 24 kmph when 9 compartments are attached, the maximum number of compartments that can be carried by the engine is

Answer & solution

  • A

    49

  • 48

  • C

    46

  • D

    47

Solution

18 ∝ 9

42 ∝ x; Here x = number of compartments

1842=9x

Simplifying, x = 49, but this is with reference to maximum speed. Hence number of compartments would be one less in order to run i.e. 48.

Hence, option (b).

CAT 1999 QA Q6: The speed of a railway engine is 42 kmph when no compartment is attached, and the reduction in speed is direct — Solution | TheCATExam