Question

A dollar bill is about 15.5 cm long. If seventeen trillion dollar bills were laid end to end around the Earth's equator, how many times would they encircle the planet? Take the radius of the Earth at the equator to be about 6378 km.

Answer 1

Answer:

The dollar bills would encircle earth 65753.1 times

Step-by-step explanation:

We have

Length of dollar bill = 15.5 cm

Total dollar bills = 17 trillion = $17\times 10^{12}$

Thus the length of 17 trillion dollar bills equals

$15.5\times 17\times 10^{12}cm\\\\=263.5\times 10^{12}cm\\\\=\frac{263.5\times 10^{12}}{10^{5}}km\\\\=263.5\times 10^{7}km$

Now taking shape of earth as a perfect sphere the circumference of earth becomes

$C=2\pi r\\\\=2\times \pi \times 6378km\\\\=40074.1558km$

Thus the number of times the dollar bills would encircle earth equals

$\frac{263.5\times 10^{7}km}{40074.1558km}=65753.21times$