The task is to generate the correct answer for a given math problem.

Q: Problem: a train 300 m long is running with a speed of 68 kmph . in what time will it pass a man who is running at 8 kmph in the same direction in which the train is going ?

A: 18 sec .
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Q: Problem: what is the greatest prime factor of 2 ^ 10 - 1 ?

A: 3
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Q: Problem: in a group of 100 cars , 49 cars do not have air conditioning . if at least 51 cars have racing stripes , what is the greatest number of cars that could have air conditioning but not racing stripes ?

A:
49
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