# I am not sure where to even begin

*label*Mathematics

*timer*Asked: May 31st, 2015

**Question description**

The Sahara Desert covers about 8.3 x 10^13 square feet.

The average depth of sand in the Sahara Desert is 200 ft.

A grain of sand has a volume of approximately 1.3 x 10^-9 cubic feet.

Which of the following is the best estimate of the number of grains of sand in the Sahara Desert?

A. 10^22

B. 10^23

C. 10^24

D. 10^25