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

Q: Problem: a man can do a piece of work in 7 days , but with the help of his son , he can finish it in 3 days . in what time can the son do it alone ?

A: 4 1 / 5
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Q: Problem: if the radius of a circle is decreased 60 % , what happens to the area ?

A: 84 % decrease
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Q: Problem: you buy a piece of land with an area of â ˆ š 1600 , how long is one side of the land plot ?

A:
40
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