A and B do a job together in two hours.Working alone A does the job in 5 hours.How long will it take B to do the job alone?
Person A does 1/5 of the job in an hour.
Person B does 1/x of the job in an hour.
A and B do 1/5+1/x of the job in an hour.
1/5+1/x = 1/2.
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