Question

The astronomical unit (AU) is the mean distance from the sun to the earth.

1 AU = 1.5 × 10,superscript,8,baseline, km (kilometers)



If a comet is 2.3 AU from the earth, how many km away is the comet?

Answer Options with 5 options
A.
3.45 × 10,superscript,8,baseline, km

B.
6.52 × 10,superscript,7,baseline, km

C.
3500 km

D.
3.45 × 10,superscript,10,baseline, km

E.
6.52 × 10,superscript,10,baseline, km

Answer 1

A. 3.45 x 10^8 km Since 1 AU is 1.5x10^8 and the comet is 2.3 AU away from Earth, the answer is a simple matter of multiplication. So: 1.5x10^8 km * 2.3 = 3.45x10^8 km Of the available options, option "A" matches exactly.

Answer 2

By definition, we have to
1 AU = 1.5 * 10 ^ 8Km
a comet is 2.3 AU from the earth, which means that we must transform this unit to kilometers.
2.3 AU = (2.3) * (1.5 * 10 ^ 8) = 3.45 * 10 ^ 8km
answer
3.45 × 10,superscript,8,baseline, km