It takes Maria 1 1/2 hours to deliver newspapers every morning. Hal can deliver the papers alone in 1 hour. How fast can they deliver the papers if they work together?

How do I set up this problem? Thank you

1 answer

rate combined=sum of rates= 1trip/1.5hr + 1trip/1hr= 2.5trips/1.5hr

time to deliver= trips/rate= 1.5/2.5=3/5 hr