Another rational equation word problem

[Steph Annie]

Rational equation word problem. How to set up?

"You have promised your parents that you would wash and clean the family car before they get home, which is in 20 minutes and you have not started the job. You estimate that it will take you 45 minutes to do a good job. Your sister says she can do the same job in 30 minutes. If you and your sister work together, can you finish the job before your parents get home?"

 

[DrPhil]

Rational equation word problem. How to set up?

"You have promised your parents that you would wash and clean the family car before they get home, which is in 20 minutes and you have not started the job. You estimate that it will take you 45 minutes to do a good job. Your sister says she can do the same job in 30 minutes. If you and your sister work together, can you finish the job before your parents get home?"

I would like to see your work on this.

 

[HallsofIvy]

Rational equation word problem. How to set up?

"You have promised your parents that you would wash and clean the family car before they get home, which is in 20 minutes and you have not started the job. You estimate that it will take you 45 minutes to do a good job.

So your "rate of work" is "one job per 45 minutes" is 1/45 "job per minute".

Your sister says she can do the same job in 30 minutes.

Your sister's "rate of work" is 1/30 "job per minute".

If you and your sister work together, can you finish the job before your parents get home?"

"rates" add.