Ruby is moving from Minneapolis to Chicago, which is 400 miles away. She is traveling at an average speed of 50 miles per hour. Ruby stops for gas after a couple of hours and wonders how much further she needs to go.
If y represents distance and x represents time, which linear equation would indicate the amount of miles Ruby still has to travel to Chicago?
a.) y = - 50x + 400
b.) y = - 400x + 50
c.) y = 50x - 400
d.) y = 400x - 50