Astronomy

I need help with 159 and 160.

 

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

159.

the speed of light is 186,000 miles/second
time is 365 days -> convert to seconds

1day=86400 seconds
365 days =365*86400 seconds=31536000seconds

distance=speed*time

186,000 miles/second*31536000seconds
=186,000 miles*31536000
=186,000 miles*31536000
=5.88 trillion miles
=5.866*10^12miles

160.

93,000,000miles/(186,000(miles/second ))
= (93,000,000/186,000)seconds
=500 seconds
= 5*10^2 seconds

 

The conversion factor part of the question threw me into a loop.