A cylindrical water tank has a diameter of 14 meters and a height of 20 meters. A water truck can fill (PIE) cubic meters of the tank every minute. How long will it take the water truck to fil the water tanhk from empty to half full.
qa is 8 hours 10 minutes. Fairly simple question EXCEPT. Volume pie r^2h = 980 and I divided this by PIE which is roughly 3. BUt solution simply splits 980 in half for the answer.
HOW DO I KNOW WHEN TO CONVERT PIE TO 3 OR JUST LEAVE IT AS 1 LIKE THIS QUESTION?
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musicdaemon
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Question asks -> what is the time for the cylinder to fill from empty to half full, So, height in this case should be 10 and not 20 ( I think you made this mistake, that is why you get 980)
Thus volume = pi*(r^2)*h
= pi*(7^2)*10
= 490pi cubic meters
Time Req = volume/Rate = (490pi)/pi = 490 min
Regarding when to convert pi in 3 (correct value 3.14), never do that until the last step. Most of the times “pi” gets cancelled by some other term, as seen above.
Thus volume = pi*(r^2)*h
= pi*(7^2)*10
= 490pi cubic meters
Time Req = volume/Rate = (490pi)/pi = 490 min
Regarding when to convert pi in 3 (correct value 3.14), never do that until the last step. Most of the times “pi” gets cancelled by some other term, as seen above.
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