Bunuel wrote:
macjas wrote:
A pool which was 2/3 full to begin with, was filled at a constant rate for 5/3 hours until it was until it was 6/7 full. At this rate, how much time would it take to completely fill this pool if it was empty to begin with?
A. 8 hrs 45 mins.
B. 9 hrs.
C. 9 hrs 30 mins.
D. 11 hrs 40 mins.
E. 15 hrs 30 mins .
\(\frac{6}{7}-\frac{2}{3}=\frac{4}{21}\) of the pool wad filled in \(\frac{5}{3}\) hours.
So, to fill the pool completely at this rate it would take \(\frac{(\frac{5}{3})}{(\frac{4}{21})}=8\frac{3}{4}\) hours or 8 hours and 45 minutes.
Answer: A.
Bunuel, this problem is fairly simple but what has confused me a little bit was your approach.
Are we always able to use Total Time \(\frac{5}{3}\) divided by Total Work \(\frac{4}{21}\) as a formula to give us the amount of Time it will take to complete the entire task?
I thought that Total Time \(\frac{5}{3}\) divided by Total Work \(\frac{4}{21}\) gave us \(1/Rate\)
Thank you for all your great posts. They are helping me get my quant score up significantly. Work/Rate problems sometimes stump me for some reason.
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