A can complete a project in 20 days and B can complete the same project in 40 days. If A and B start working on the project together and A quits 10 days before the project is completed, in how many days will the project be completed?	Choose the correct choice from the following answers
A) 18 days  B) 20 days  C) 26.67 days  D) 16 days  E) 12 days
Let X = the number of days taken to complete the project.   The amount of work done by A is (x-10) * (1/20).   The amount of work done by B is (x) * (1/40).   (1/20)*(x-10) + (1/40)*(x) = 1   (x/20) + (x/40) - (10/20) = 1   3x/40 = 3/2   x = 20   Therefore, the answer is 20 days: 20.
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A can complete a project in 20 days and B can complete the same project in 40 days. If A and B start working on the project together and A quits 10 days before the project is completed, in how many days will the project be completed?