A cylindrical water tower with radius 28 m and height 10 m is 3/4 full at noon. Every minute, .08π m3 is drawn from tank, while .03π m3 is added. Additionally, starting at 1pm and continuing each hour on the hour, there is a periodic drain of 4π m3. From noon, how many hours will it take to drain the entire tank?  Choose the correct option: A) 840 2/7 B) 820 6/7 C) 821 D) 821 3/7 E) 840
initial volume = (3/4)×∏×28²×10 = 5880∏   Relative Drain/ min = .08∏ - .03∏ = .05∏ m³/min drain   Relative drain / hour .08  - .03= 
<gadget id="calculator">.08  - .03</gadget>
<output>0.05</output>
.05∏ m³/min drain   Relative drain / hour= .05∏×60 = 3∏ m³/ hr   Every one hour starting from 1pm, 4∏ m³ of water is drained. It means that only at the hour the water is drained and NOT “in that 1 hour“   So after 1 hr the relative drain would be 3∏ + 4∏ = 7∏m³ of water drain   What i did initially was formed an equation 5880∏   3  + 4= 
<gadget id="calculator">  3  + 4</gadget>
<output>7</output>
7∏m³ of water drain   What i did initially was formed an equation 5880∏= 7∏×n (n is the number of hrs) so ended up with 840. 840
<result>E</result>
A cylindrical water tower with radius 28 m and height 10 m is 3/4 full at noon. Every minute, .08π m3 is drawn from tank, while .03π m3 is added. Additionally, starting at 1pm and continuing each hour on the hour, there is a periodic drain of 4π m3. From noon, how many hours will it take to drain the entire tank?