Hey there! I'm happy to help!
We see that light travels 186,000 miles per second. How many miles is this per minute. Well, there are 60 seconds a minute, so we multiply by 60!
186,000×60=11160000
And there are 60 minutes in an hour, so we multiply by sixty again!
11160000×60=669600000
Now, we need to write this in scientific notation. To do this, we move the decimal back enough places to have a one digit number, and we multiply that one digit number by 10 to the power of how many places you moved the decimal back.
In the number 669600000 we can move the decimal point back 8 times which gives us 6.696 (we don't need the zeroes after a decimal) multiplied by 10 to the 8th power because we moved the decimal back eight places.
This can be written as 6.696×10^8, which is closest to the answer option 6.7×10^8 miles.
Have a wonderful day! :D
