Can you help me with physics?

Question

A dollar bill is about 15.5 cm long. If 8 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 6378 km.

Answer 1

(0.000155 km X 8 trillion) / ( 2 X 3.14 X 6378km) = number of times would they encircle the planet

Answer 2

8 trillion x .000155 km / 6378 km = how many times around equator.