Mike can complete a project in 60 minutes͵ and if Mike and Walter both work on the project͵ they can complete it in 40 minutes. How long will it take Walter to complete the project by himself?

Answer 1

Mike (1/60) project/min

Walter (w project/min)

together

(1 + 60 w)/60 project /min

[(1+60 w)/60 ] 40 = 1 project

1 + 60 w = 6/4

60 w = .5

w = .0083333

1/w = min/project = 120 minutes