SOLUTION: How long does it take to fill a 4000 l pool at a rate of 20l/minute. The pool springs a leak after 20 minutes at 2 L/minute. How long from the start to fill the pool?
Question 1098908: How long does it take to fill a 4000 l pool at a rate of 20l/minute. The pool springs a leak after 20 minutes at 2 L/minute. How long from the start to fill the pool? Found 2 solutions by ikleyn, josmiceli:Answer by ikleyn(52787) (Show Source): You can put this solution on YOUR website! .
20 minutes to fill 29*20 = 400 liters,
and then additional = = 200 minutes
to fill the remaining 4000-400 = 3600 liters at the rate of (20-2) = 18 liters per minute.
In total, 220 minutes, or 3 hour 40 minutes.
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website! [ liters in pool ] / [ liters/min filling rate ] = [ min to fill pool ] min filling time
The pool fills in 200 min
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[ liters/min ] x { min ] = [ liters ] liters put into pool after 20 min liters left in pool
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Let = the elapsed time in minutes after 20 min
during which pool both fills and empties until it is full
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Time to empty 1 pool at 2 liters/min: min
Add rates to get final rate of filling:
[ 1 pool / 200 min ] - [ 1 pool emptied / 2000 min ] = [ 9/10 pool filled / t min ]
Multiply both sides by min
Now add in the initial 20 min
This is 220 min to fill the pool
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Definitely feel free to get another opinion ( if needed )