word problem

Question

andrew can paint the neighbors house 2 times as fast as bailey the year andrew and bailey worked together , it took the 7 days. how many days would it take each tot paint the house

Answer 1

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.