BRC Problem of the Month - September 1999

Before a recent rain storm I left an empty paper cup outside. The cup was 9 cm high.  Its radius at the bottom was 2.5 cm and 3.6 cm at the top.  After the storm had passed, the water level was 5.1 cm above the bottom of the cup.  
(a)  How much rain  did we have in that storm?   
(b) The area of my yard is approximately 2800 and the storm lasted four hours.  How many cubic meters of water per hour fell on my yard during the storm?

Hint:  The volume of a cone with height h and base radius r is

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