SOLUTION: Mr. Johnson paints 5/9 of his house in 10 hours, and then is joined on the job by his neighbor, Mr. Prima. Together, they finish painting the house in 3 hours. How long would it

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Mr. Johnson paints 5/9 of his house in 10 hours, and then is joined on the job by his neighbor, Mr. Prima. Together, they finish painting the house in 3 hours. How long would it       Log On


   



Question 731547: Mr. Johnson paints 5/9 of his house in 10 hours, and then is joined on the job by his neighbor, Mr. Prima. Together, they finish painting the house in 3 hours. How long would it have taken Mr. Prima to do the entire job himself?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Mr. Johnson paints 5/9 of his house in 10 hours, and then is joined on the job by his neighbor, Mr. Prima.
Together, they finish painting the house in 3 hours.
How long would it have taken Mr. Prima to do the entire job himself?
:
Find how many hrs for Johnson to do the house alone
5%2F9h = 10
h = 10*9%2F5
h = 18 hrs
:
Let p = time for Prima to do it alone
Let the completed job = 1
J worked 13 hrs, P worked 3 hrs
13%2F18 + 3%2Fp = 1
Multiply by 18p, resulting in
13p + 18(3) = 18p
54 = 18p - 13p
54 = 5p
p = 54/5
p = 10.8 hrs