#### harpazo

##### Junior Member

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- Jan 31, 2013

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Algebra Essentials

Michael Sullivan

Textbook: College Algebra Edition 9

One light-year is defined by astronomers to be the distance that a beam of light will travel in 1 year or 365 days. If the speed of light is 186,000 miles/second, how many miles are in a light-year? Express your answer in scientific notation.

Solution:

I know from reading the question that light travels at 186,000 miles for each second.

There are 3600 seconds in one hour. I then proceed to multiply 186,000 by 3600 seconds to get 669,600,000 miles in one hour.

One day has 24 hours. So,

669,600,000 x 24 hours is

16,070,400,000 miles in one day.

So, for 365 days in one year, I multiply 16,070,400,000 x 365 days to get 5,865,696,000,000 miles in a year.

In scientific notation, the answer is expressed as follows:

5.86 x 10^12 miles per year.

Is this right? Did I mess up somewhere along the way? If there is an easier set up or equation, please share that with me here.