The speed of light is 3 x 10^8 meters/seconds. If the sun is 1.5 x 10^11 meters from earth, how many seconds does it take light to reach the earth? Express your answer in scientific notation.

d = r x t  distance is equal to the rate of speed multiplied by time.  Thus t = d ÷ r  This is the relationship we'll use to solve this problem.  Now, let's organize our data:
 r = 300,000,000 m/s  Let's write this using scientific notation: r = 3 x 108 m/s d = 1.5 x 1011 m t = d ÷ r  ⇒  t = 1.5 x 1011 ÷ 3 x 108  or: t = .5 x 103  That is: 500 seconds or about 8.3 minutes so basically the answer is the sunlight takes about 8 minutes and 20 seconds to reach earth.