The task is to generate the correct answer for a given math problem.
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Question: Problem: dhoni bought 5 toys with the average cost of $ 10 . if david also buys the sixth toy with the price of $ 16 , what is the average ( arithmetic mean ) price of those 6 toys ?

Answer: $ 1


Question: Problem: a train crosses a bridge of length 200 m in 10 seconds and a lamp post on the bridge in 5 seconds . what is the length of the train in metres ?

Answer: 200 m


Question: Problem: a can do a job in 9 days and b can do it in 27 days . a and b working together will finish twice the amount of work in - - - - - - - days ?

Answer:
18 days