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 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.)
The correct option is B 32
When all cars follow the police order, the time taken would be
A-N-B (1 car) = 20 + 12 =32 minutes.
A-M-N-B (2cars) = 12 + 8 + 12 = 32 minutes.
A-M-B (1 car) = 12 + 20 = 32 minutes.
32
When all cars follow the police order, the time taken would be
A-N-B (1 car) = 20 + 12 =32 minutes.
A-M-N-B (2cars) = 12 + 8 + 12 = 32 minutes.
A-M-B (1 car) = 12 + 20 = 32 minutes.
