Question 176711
A) other than the sun closest to Earth is Alpha Centauri. Its distance from Earth is about 2.4 x 10^13 mi. One light year = the distance the light travels in one year = 5.88 x 10^12 mi. How many light years is it from Earth to Alpha Centauri? 
[2.4 x 10^13 mi] / [5.88 x 10^12 mi.] = 4.0816
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B)write 200 billionths in scientific notation.
200/10^9 = 200x10^-9 = 2.0 x 10^-7
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Cheers,
Stan H.