# How to fill a car with tennis balls

if i want to fill interior of a car with tennis balls how many will be required.

How to calculate this?

if we are provided with length,breadth,height of car(height varies at each part) and radius of tennis ball.

Some one please explain it in detail.

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I removed the "logic" tag. –  Carl Mummert Feb 8 '13 at 11:45
Do you know calculus? Multivariable Calculus? Do you have any idea what shape the car's roof is? You say height varies, so we will have to assume the base is a rectangle. Do you have an equation that describes, parametrizes the roof? With only this your question is incomplete. –  user45099 Feb 8 '13 at 11:54
I know this can not be solved with out knowing the shape structure.I just want to how it can be solved. –  kevin Feb 8 '13 at 12:08
A crude approximation would be to divide the volume of the car $lbw$ by the volume of a tennis ball $4\pi r^3 / 3$ and multiply by an appropriate sphere packing density. Let's say: $0.75*lbw / (4\pi r^3 / 3)$. –  01000100 Feb 8 '13 at 12:12