Debra and Alexandria can finish a plowing job in two hours if they work together. Debra can do the job in 7 hours by herself. How long would it take Alexandria to finish the same job alone?

2 hours 48 minutes

Step-by-step explanation:

Debra=1 plowing job / 7 hours

Debra+Alexandra=1 plowing job / 2 hours

1/2-1/7

=7/14-2/14

=5/14

=1/14/5 (Alexandra can do 1 unit of plowing job per 14/5 hours)

14/5 hour=2 hours 48 minutes (hope hits helps)

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