SOLUTION: I have a problem but cannot figure out the equation (formnula) necessary to find the answer. All the examples I can find give me the rates but not the total time, but this one is t

Algebra ->  Rate-of-work-word-problems -> SOLUTION: I have a problem but cannot figure out the equation (formnula) necessary to find the answer. All the examples I can find give me the rates but not the total time, but this one is t      Log On


   



Question 301708: I have a problem but cannot figure out the equation (formnula) necessary to find the answer. All the examples I can find give me the rates but not the total time, but this one is the opposite.
Working together, Jenny and Natalie can mop a warehouse in 5.14 hours. Had she done it alone it would have taken Natalie 12 hours. How long would it take Jenny to do it alone?
Thank you for your help.
Jonathan

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
Working together, Jenny and Natalie can mop a warehouse in 5.14 hours. Had she done it alone it would have taken Natalie 12 hours. How long would it take Jenny to do it alone?
.
Let x = number of hours if Jenny worked alone
then
5.14(1/x + 1/12) = 1
Multiplying both sides by 12x we have:
5.14(12 + x) = 12x
61.68 + 5.14x = 12x
61.68 = 6.86x
9 hours = x