The task is to generate the correct answer for a given math problem.
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Question: Problem: excluding stoppages , the average speed of a bus is 60 km / hr and including stoppages , the average speed of the bus is 15 km / hr . for how many minutes does the bus stop per hour ?

Answer: 4

Question: Problem: two trains of length 100 meters and 200 meters are 450 meters apart . they are moving towards each other on parallel tracks , at speeds of 90 km / h and 72 km / h . after how many seconds will the trains meet ?

Answer: 10

Question: Problem: find the area of a parallelogram with base 10 cm and height 20 cm .

Answer:
200