Sally can paint a room in 4 hours while it takes Steve 5 hours to paint the same room.How long would it take them if they paint the room together?

Question

Please show the work. Thank you

Answer 1

Hi Chris,

(Rate to paint a room)X( time taken to finish)= 1    

(Painting is done if a fraction then unfinished job)

Rate to paint a room = 1/(time taken to paint the room)

Rate at which Sally paint = 1/4

Rate at which Steve paint = 1/5

 

(Rate at which Sally Paints)t + (Rate at which Steven Paints)t = 1

(1/4)t + (1/5)t = 1

             9t20  = 1

                 t  = 20/9

                    =2 2/9

It will take Sally and Steve 2.22 hours to paint the entire room