Estimation - Number of golf balls that can fit in a School Bus

Guess Estimate the number of golf balls that can fit in a School Bus

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May 17, 2021

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a year ago · 3 likes · My PM Interview

Clarifying Questions -

Do we consider the school bus with seats or without seats?
A) For the purpose of this question, let’s consider that the school bus has seats inside.

Known:

1 cubic foot = 1728 cubic inches.
The radius of a Golf ball = 0.85 inches (or 2.1 cm)

Calculation:

Size of a School Bus (assumption),

= 20 ft long x 8 ft wide x 6 ft high

= 960 cubic feet

or 960 x 1728 cubic inches (1 cubic foot = 1728 cubic inches)

= 1658880 cubic inches.

The volume of a Golf Ball,

= (4/3)*π*r*r*r

= (4/3)*π*0.85*0.85*0.85

~ 2.5 cubic inches (or 38.8 cubic cm)

Therefore,

Number of Golf Balls that can be accommodated,

= (Volume of the school bus) / (Volume of the golf ball)

= 1658880 / 2.5

= 660,000 golf balls

Now, seats will take up some space (assuming 25%),

Number of Golf Balls that can be accommodated (with seats),

= 75% of 660,000

= 495,000 golf balls

Now, let’s take into consideration “Best Packing Efficiency” of 74%
(Since golf balls are spherical in shape, there will be some void gaps of some volume between the spheres)

Therefore, the number of golf balls that can actually be accommodated in a school bus,

= 74% of 495,000

= 366,000 golf balls.

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