SOLUTION: It takes Jonathan 2/3 as long as it takes Juancho to paint a car. If together Jonathan and Juancho take 12 hrs, how long would it take Juancho to do the work alone?

Algebra ->  Rate-of-work-word-problems -> SOLUTION: It takes Jonathan 2/3 as long as it takes Juancho to paint a car. If together Jonathan and Juancho take 12 hrs, how long would it take Juancho to do the work alone?       Log On


   



Question 389489: It takes Jonathan 2/3 as long as it takes Juancho to paint a car. If together Jonathan and Juancho take 12 hrs, how long would it take Juancho to do the work alone?
Found 2 solutions by ankor@dixie-net.com, josmiceli:
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
t takes Jonathan 2/3 as long as it takes Juancho to paint a car.
If together Jonathan and Juancho take 12 hrs, how long would it take Juancho to do the work alone?
:
let x = time required by Ju alone
then
2%2F3x = time required by Jo alone
:
Let the completed job = 1; (a painted car)
:
12%2F%28%282%2F3%29x%29 + 12%2Fx = 1
multiply by 2%2F3x, results:
(12) + 2%2F3(12) = 2%2F3x
12 + 8 = 2%2F3x
20 = 2%2F3x
multiply by 3
3(20) = 2x
2x = 60
x = 30 hrs, Ju alone
:
:
Check solution,
2%2F330 = 20 hrs, Jo alone
12%2F20 + 12%2F30 = 1
.6 + .4 = 1; confirms our solution

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let t = Juancho's time to paint a car
Then %282%2F3%29%2At = Jonathan's time to paint a car
1%2Ft+%2B+1%2F%282t%2F3%29+=+1%2F12
multiply both sides by t
1+%2B+3%2F2+=+t%2F12
Multiply both sides by 12
12++%2B+18++=+t
t+=+30
It takes him 30 hrs alone