David an Fiona have a house painting business. It takes Fiona 3 days to paint a certain house. David could paint the same house in 4 days. How long would it take them to paint the house if David and Fiona worked together?

Question

anonymous · Answer

@agent0smith  Do you know how to o this?

agent0smith · Answer

this is the way i do them$$\Large \frac{ 1 }{ t } = \frac{ 1 }{ 4 }+\frac{ 1 }{3 }$$solve for t

anonymous · Answer

that's what I did but I got the answer 7/2 as the final answer.but that's wrong. Can you go throught the steps please?

anonymous · Answer

sorry 7/12

agent0smith · Answer

$$\Large \frac{ 1 }{ t } = \frac{ 7 }{ 12 }$$
that doesn't mean the answer is 7/12

anonymous · Answer

oh would I cross Multiply now?

agent0smith · Answer

Yes. Orrrr just flip both sides since they are both fractions.

1/t becomes t/1.

anonymous · Answer

Alright, thankyou! :) Can you help me with one more?