Answer:
Here's the conversion factor you need:
1 Kilometer = 39370 inches
So, for your question we want to go 405,696 km....
405696 km x 39370 inches/ 1 km = 15972283464 inches
15972283464 inches x 2.54 x10^8 atoms/1 inch = 4.05 x 10^18 atoms
There are 7 digits from decimal to 1st digit, and it's coming from right, so exponent will be in negative 7
In short, Your Answer would be: Option C) <span>6.75 × 10-7
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Hope this helps!