SOLUTION: Tom and john together can paint a room in 2 hours. If tom is painting the room alone, he can only complete the task in 6 hours. How long will jasper take to paint a room all by him

Algebra ->  Rate-of-work-word-problems -> SOLUTION: Tom and john together can paint a room in 2 hours. If tom is painting the room alone, he can only complete the task in 6 hours. How long will jasper take to paint a room all by him      Log On


   



Question 1185333: Tom and john together can paint a room in 2 hours. If tom is painting the room alone, he can only complete the task in 6 hours. How long will jasper take to paint a room all by himself?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Tom and john together can paint a room in 2 hours.
If tom is painting the room alone, he can only complete the task in 6 hours.
How long will "JOHN" take to paint a room all by himself?
:
let j = time required by John to do it by himself
let the completed job = 1
Each will to a fraction of the job, the two fractions add up to 1
Tom + John = completed job
2%2F6 + 2%2Fj = 1
multiply by 6j, get rid of the denominators
2j + 6(2) = 6j
12 = 6j - 2j
12 = 4j
j = 12/4
j = 3 hrs, John by himself
:
:
Check, 2/6 = 1/3
1%2F3 + 2%2F3 = 1