word problems

Question

Darien vacuums the carpet at his church once a week. It takes him 4 hours. It takes his cousin Nikki 2 hours. How long will it take them if they work together? Include units in your answer.

Answer 1

Darien gets 1/4 of the job done every hour

 

Nikki gets 1/2 of the job done every hour

 

how many hours do they work together to get the entire job done (1 represents the whole job)

 

x = the number of hours

 

x/4 + x/2 = 1

 

x/4 + 2x/4 = 1

 

3x/4 = 1

 

x = 4/3

 

4/3 hours which is 1 and 1/3 hours

 

this equals 1 hour 20 minutes