SOLUTION: The diamerter of the Mily Way disc is approximately 9 x 10^20 meters. How long does it take light, traveling in 10^16 m/year to travel across the diamerter of the Milky Way? I a

Question 70805This question is from textbook Beginning Algebra
: The diamerter of the Mily Way disc is approximately 9 x 10^20 meters. How long does it take light, traveling in 10^16 m/year to travel across the diamerter of the Milky Way?
I am really confused on this one, and need some help.
ThanksThis question is from textbook Beginning Algebra

Found 2 solutions by josmiceli, jim_thompson5910:
Answer by josmiceli(6785) (Show Source):
You can put this solution on YOUR website!
This is just distance/rate = time
meters / m/yr
= time in years
years
or 90,000 years

Answer by jim_thompson5910(21685) (Show Source):
You can put this solution on YOUR website!
Look at this as a rate problem, but with much larger numbers. Use the equation d=rt. Let d=9 x 10^20 meters (diameter of galaxy) and r=10^16 m/year (speed of light in meters per year).
Solve for t by dividing both sides by 10^16 m/yr
Divide the numbers by subtracting exponents. Remember similar units cancel

So it takes 9 x 10^4 *(yr) or 90,000 yrs for light to go across the diameter of the Milkyway.