CAT 2017 Slot 1 DILR · Question 8
Four cars need to travel from Akala (A) to Bakala (B). Two routes are available,
one via Mamur (M) and the other via Nanur (N). The roads from A to M, and from N to B, are both
short and narrow. In each case, one car takes 6 minutes to cover the distance, and each
additional car increases the travel time per car by 3 minutes because of congestion. (For
example, if only two cars drive from A to M, each car takes 9 minutes.) On the road from A to N,
one car takes 20 minutes, and each additional car increases the travel time per car by 1 minute.
On the road from M to B, one car takes 20 minutes, and each additional car increases the travel
time per car by 0.9 minute.
The police department orders each car to take a particular
route in such a manner that it is not possible for any car to reduce its travel time by not
following the order, while the other cars are following the order.
A new one-way road is built from M to N. Each car now has three possible routes to travel
from A to B: A-M-B, A-N-B and A-M-N-B. On the road from M to N, one car takes 7 minutes
and each additional car increases the travel time per car by 1 minute. Assume that any
car taking the A-M-N-B route travels the A-M portion at the same time as other cars
taking the A-M-B route, and the N-B portion at the same time as other cars taking the
A-N-B route.
If all the cars follow the police order, what is the minimum travel
time (in minutes) from A to B? (Assume that the police department would never order all
the cars to take the same route.)
- A.26
- B.32
- C.29.9
- D.30
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