SOLUTION: Hi there, I would appreciate some help with the next problem: Kristal can wax a floor in 16 minutes. One day her friend Perry helped her and it only took 5.76 minutes. How lon

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Question 429946: Hi there, I would appreciate some help with the next problem:
Kristal can wax a floor in 16 minutes. One day her friend Perry helped her and it only took 5.76 minutes. How long would it take Perry to do it alone?
Found 2 solutions by ewatrrr, htmentor:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!


Hi

Let x represent the time it  would take Perry to do it solo

Question states*** Per minute the equalizer

 1/16 + 1/x = 1/5.76 

Solving for x

36x + 576 =  100x     |multiplying thru by 576x so as all denominators= 1

     576 = 64x

     x = 9 minutes, time it  would take Perry to do it alone

Answer by htmentor(1343) About Me  (Show Source):
You can put this solution on YOUR website!
Kristal's rate = 1 floor in 16 min. = 1/16 floors per min.
Working together their rate = 1 floor in 5.76 min. = 1/5.76 floors per min.
We need to determine Perry's rate, so we need to equate their combined rate with the sum of the individual rates.
Let Perry's time = x
In equation form, we can write:
1/16 + 1/x = 1/5.76
Solve for x:
(x+16)/16x = 1/5.76 -> 5.76(x+16) = 16x -> 10.24x = 92.16 -> x = 9
So, Perry would take 9 mins. to do the floor alone.