Problema Solution
A homeowner estimates that it will take him 9 days to roof his house. A professional roofer estimates that he could roof the house in 4 days. How long will it take if the homeowner helps the roofer?
Answer provided by our tutors
let
t = the days they need to roof the house when working together
the rate of the homeowner is 1/9 roofs per day
the rate of the professional roofer is 1/4 roofs per day
t(1/9) + t(1/4) = 1
by solving we find
t = 36/13
t = 2.77 days
t = 2 days 18.5 hours
click here to see the step by step solution of the equation
it will take them 2.77 days or 2 days and 18.5 hours to roof the house together.