An hourglass consists of two sets of congruent composite figures on either end. Each composite figure is made up of a cone and a cylinder:

Hourglass with sand measuring 54 millimeters high
© 2011 Jupiterimages Corporation

Each cone of the hourglass has a height of 18 millimeters. The total height of the sand within the top portion of the hourglass is 54 millimeters. The radius of both cylinder and cone is 8 millimeters. Sand drips from the top of the hourglass to the bottom at a rate of 10π cubic millimeters per second. How many seconds will it take until all of the sand has dripped to

Question

An hourglass consists of two sets of congruent composite figures on either end. Each composite figure is made up of a cone and a cylinder:

Hourglass with sand measuring 54 millimeters high
© 2011 Jupiterimages Corporation

Each cone of the hourglass has a height of 18 millimeters. The total height of the sand within the top portion of the hourglass is 54 millimeters. The radius of both cylinder and cone is 8 millimeters. Sand drips from the top of the hourglass to the bottom at a rate of 10π cubic millimeters per second. How many seconds will it take until all of the sand has dripped to

anonymous · Answer

64pi * (54-18)
+ 64pi * 18/3
---------------
equals total volume