18. A taxi company's repair station has 7 taxis to be repaired. If 1 worker repairs these 7 cars, the repair times are $12, 17, 8, 18, 23, 30, 14$ minutes, respectively. Each taxi incurs an economic loss of 2 yuan for every minute it is out of service. Now, 3 workers with the same work efficiency are working separately. To minimize the economic loss, what is the minimum loss in yuan?
【Analysis】To minimize the loss, the total time spent on repairing and waiting for each car should be minimized. With 3 workers repairing 7 cars, to minimize the total, each worker should repair as close to the same number of cars as possible, so 2 workers each repair 2 cars, and 1 worker repairs 3 cars. When the worker repairing 3 cars works on the first car, 1 car is being repaired and 2 cars are waiting, so the time is counted 3 times. When working on the second car, 1 car is being repaired and 1 car is waiting, so the time is counted 2 times. When working on the third car, 1 car is being repaired, so the time is counted 1 time. For the workers repairing 2 cars, when working on the first car, 1 car is being repaired and 1 car is waiting, so the time is counted 2 times. When working on the second car, 1 car is being repaired, so the time is counted 1 time. Therefore, the repair time for 1 car is counted 3 times, the repair time for 3 cars is counted 2 times, and the repair time for 3 cars is counted 1 time. Thus, the minimum total time is $8 \times 3+(1) 2+14+17 \times 2+18+23+30=181$ minutes, and the minimum loss is $2 \times 181=362$ yuan.