Janet an experienced shipping clerk can fill a certain order in 5 hours . tom a new clerk needs 8 hours to do the same job. working together how long will it take them to fill the order

Janet can fill a certain order in 5 hours, therefore she performs 1/5 of the order within 1 hour.

Tom needs 8 hours to do the same job, therefore he performs 1/8 of the order within 1 hour.

Working together, they make 1/5 + 1/8 orders within 1 hour.

Let t mean the number of hours they need. Then we have equation:

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