February 12, 2001
Problem of the Month

The Water Tank Problem

There is a cubical water tank that is one mile long, one mile wide, and one mile deep. It is completely filled with water.

A hole is punched in it at the bottom, and water begins to flow at the rate of one gallon per second.

How long does the tank take to empty?

Solution to the Problem:

Since 1 cubic foot of water is equivalent to 7.48 gallons of water, it would take almost 34,890 years to empty!

One mile = 5,280 feet, so one cubic mile = 5280 x 5280 x 5280 cubic feet which equals 147,197,952,000 cubic feet.

Multiply by 7.48 to obtain the number of gallons of water in the tank: 1,101,040,680,960 gallons!

Draining at one gallon per second, this represents the number of seconds it would take to drain the tank!

Divide by 60 to convert to minutes;
Divide by 60 again to convert to hours;
Divide by 24 to convert to days;
And finally divide by 365.25 to convert to years!
The number of years is approximately 34,889.87!

Correctly solved by:

1. Tony Alteparmakian	Bakersfield, CA
2. David Powell	Winchester, VA
3. Clark Nesselrodt	Winchester, VA
4. Erin McGinnis	Winchester, VA

Send any comments or questions to: David Pleacher