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

Q: Problem: if 5 a = 3125 , then the value of 5 ( a - 3 ) is :

A: 25
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Q: Problem: two trains each 120 m in length each , are running on two parallel lines in opposite directions . if one goes at the speed of 85 km / h while the other travels at 65 km / h . how long will it take for them to pass each other completely .

A: 10.07 sec
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Q: Problem: a train passes a station platform in 30 sec and a man standing on the platform in 20 sec . if the speed of the train is 54 km / hr . what is the length of the platform ?

A:
60 
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