The distance between earth and mars is 225 million km. when converted using the conversion factor 1 au = 1.5 × 108 km, the distance between the planets is . the astronomical unit (au) is a light-year.

I guess the problem is asking for the distance between Earth and Mars in Astronomical Units (AU).

Since 
and the distance between the two planets is

we can convert this distance into AU by using the following proportion:


from which we find

To use anything transparent

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