Huzefa K. answered • 11/13/14

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Let's say that A is the rate at which Andrew paints, and B is the rate at which Bailey paints. Accordingly:

A = 2*B

We also know that:

A*7 days + B*7 days = 1 house

Using substitution, we substitute 2*B for A

(2*B)*7 + B*7 = 1 house

21B = 1

B = 1/21 houses per day

A = 2/21 houses per day

**It would take B 21 days, and A 10.5 days.**