Answer:
3 15/17 days
Step-by-step explanation:
let the amount of work done to roof the whole house by x
Time taken by homeowner to roof his house = 11 days
In 11 days homeowner can do x work
in 1 day homeowner can do x/11 work
Time taken by professional to roof the house = 6 days
In 6 days professional can do x work
in 1 day professional can do x/6 work
In 1 day total work done, if both professional and homeowner work together
= x/6 + x/11 = (11x + 6x)/11*6 = 17x/66
17x/66 work is done by both in 1 day
we have to calculate total work done by both , to find this we multiply both side by 66/17 to eliminate it from term containing x(which is the total work done to roof the house)
17x/66 *(66/17)work is done by both in 66/17 days
x work is is done by both in 3 15/17 days.
Hence, it will take 3 15/17 days to roof the house, if the homeowner helps the roofer.
