10 Toughest Google Interview Questions and Answers

2. Estimate the Number of Tennis Balls That Can Fit Into a Plane.

Intern

Assume that there are six seats in a row and a walking space between them in a Boeing 737. Each seat has enough room for the handles and is intended for one person. Assume that a seat’s width is 0.5 meters.As a result, with 6 seats, 6*0.5=3.0m. Assume the passageway is 1.5 meters wide. 

Therefore, the plane’s overall width is 3.0 + 1.5 + 0.5 (buffer) meters.

And if a plane has 70 rows, each taking up one meter of space. 5 meters in front of and 5 meters behind each row

So the plane’s height is 80 meters.

The tennis ball has a radius of around 3 cm (0.03 m).

Tennis ball volume = 4/3(pi r3) = 1.33*0.000027*pi

Imagine a Boeing 747 as a cylinder with a 5 m radius and an approximate length (height) of 80 m.

Boeing 747 volume = pi*(r2)*h = 25*80*pi

Tennis balls that can fit on a Boeing 747 are equal to (25*80)/(1.33*0.000027). Six million tennis balls

Tennis balls can’t completely fill the capacity of the cabin; their random packing efficiency is only about 64%; hence, multiplying 6,000,000 by.64 yields 3,840,000.