Question

It takes Sally 4 hours to deliver newspapers. If Kathy works alone, it takes her 6 hours. How long would it take them working together to deliver all of the newspapers?

Answer 1

Sally's rate is 1/4 job per hour. 
Kathy's rate is 1/6 job per hour. 

Can you solve the rest? Scroll down if you can't!





1/4 + 1/6 
= 3/12 + 2/12 
= 5/12
5/12 x 6 = 30/60.

Answer: It will take them half an hour combined.