dan and dave can work together to paint a house in 4 days. dan works 2 times faster. how long would it take each of them to paint the house alone

Answer 1

dave's rate ---- 1/x
dan's rate = 1/(2x)
combined rate = 1/x + 1/2x = 3/(2x)

3/(2x) = 1/4
2x = 12
x = 6

Dave can paint it in 6 days, Dan would take 12 days.