Space Teaser

What does the Earth and the International Space Station (ISS) have in common? They both rotate in an easterly direction. The earth rotates easterly around its spin axis and the ISS rotates easterly as it cycles north and south of the equator.

Channel your inner Neil Armstrong and figure out how many times the ISS travels around the Earth in 24 hours!

Here's the problem:
Given the International Space Station (ISS) orbits once around the earth every 90 minutes, how many times does the ISS orbit around earth in a 24-hour period?

Answer: 16