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

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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Q: Problem: what is the units digit of 17 ^ 83 × 13 ^ 82 × 11 ^ 67 ?

A: 4
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Q: Problem: in a certain supermarket , a triangular display of cans is arranged in 9 rows , numbered 1 through 9 from top to bottom . each successively numbered row contains 3 more cans than the row immediately above it . if there are fewer than 120 cans in the entire display , how many cans are in the seventh row ?

A:
19
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