Pizza Galore

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Question: 

How many square feet of pizza are eaten in the United States each month? Is the answer closest to:

a)      Area of New Jersey?
b)      Area of a typical classroom?
c)       Area of Central Park?
d)      Area of a baseball stadium?
e)      Area of available office space in the new World Trade Center?

Answer: 

Approximately 150 million square feet, which is closest to choice C

Explanation:

The population of United States is 300 million. Assume that 2/3 of the people eat pizza in a month. Assume those people on average eat pizza twice a month, each time two slices. Then we have 200 million people eating 4 slices each month.

Assume the 8-slice round pizza. Estimate the radius of the pizza at 1 ft. The area of an entire pizza then is 3.14 square feet, or round to 3 for convenience. If each person eats half of that, and there are 200 million pizza eaters, that’s 150 million square feet of pizza consumed.

Now let’s see which one is the good approximation. For conversation, since 1 mile = 5280 feet, use the approximation of 1 mile = 5000 ft to get 1 square mile = 25 million square feet. So then, 150 million square feet is around 8 square miles.

a)      New Jersey is way bigger than 8 square miles, off by several orders of magnitudes.

b)      Typical classroom is way smaller than 8 square miles.

c)       Central Park is about 3 avenues wide and 50 blocks length-wise. If 1 avenue = ¼ mile and 20 blocks = 1 mile, that’s about 2.5 mile by ¾ mile, or just less than 2 square miles. That’s within one order of magnitude.

d)      Even assuming 1 mile x 1 mile size for baseball stadium, which is an overestimate (the home plate to homerun is only about 400 ft), that’s 1 square mile. Think of another way: Central Park can fit more than 1 baseball stadium, and if Central Park already is an underestimate, baseball stadium would be a worse estimate.

e)      Assume 100 stories, and even with an overestimate of each floor as 500 x 500 ft, that’s 100*250,000 = 25,000,000 square feet of overall office space, or about 1 square mile.

Besides from choice A, all others were underestimates, but choice C was the closest.