SOLUTION: I tried on this problem already (not from a textbook) and I'm not sure if I'm getting it, I've got answers ranging from 18 mins to 8.89 minutes. Here's the problem: Jack can wa

Question 134441: I tried on this problem already (not from a textbook) and I'm not sure if I'm getting it, I've got answers ranging from 18 mins to 8.89 minutes. Here's the problem:
Jack can wash a car in 16 minutes; Jill can wash the same car in 20 minutes. How long will it take both of them working together to wash the car?
This is what I've done: (16 + 20) / 2 = 18 mins
I've also tried using the example of the solution to problem 133568 and I got 8.89 mins.
I'm not sure which is correct and I'd really appreciate the help. Thank you.
Answer by checkley71(8403) (Show Source): You can put this solution on YOUR website!
YOU ARE USING THE WRONG EQUATION FOR THIS PROBLEM.
THE PROPER EQUATION IS THE PRODUCT DIVIDED BY THE SUM OF THE 2 TIMES.
16*20/(16+20)=320/36=8.889 MINUTES TO WASH THE CAR WORKING TOGETHER.
RELATED QUESTIONS
m/m^2-m-12 + 5/m+3 This is what i came up with but i'm not exactly sure how i... (answered by stanbon)

Alice and Bob start from the same position on a track and both start jogging clockwise... (answered by ikleyn)

I'm using a book called No-Nonsense Algebra by Richard Fisher. I've run into a problem... (answered by MathLover1,math_helper)

Problem is: {{{(8)/(2m+1)-(1)/(m-2)=(5)/(2m+1)}}} I've tried several ways, but can't... (answered by Alan3354,richwmiller)

Suppose you have a group of six men and three women; you want to line them up so that no... (answered by sudhanshu_kmr)

Hello, I am not really sure where to put this question...what topic it would fall... (answered by nerdybill,edjones)

I need help with this inequality: |3x-2| ( < or equal to) 5 How would I graph this... (answered by mananth)

The data in the table that follows was collected by a large car manufacturer concerning... (answered by stanbon)

I ve tried to solve this problem several times and still not getting how it works. How do (answered by shree840)