Miles per hour

Question

A bus traveled at an average rate of 60mph then reduced its average rate to 30mph for the rest of the trip. if the 189 mile trip took 4 hours determine how long the bus traveled at each rate. the time spent traveling at 60mph is: and the time spent traveling at 30mph is:

Answer 1

You have to establish your 2 equations first. They are:

 

x+y=4

60x+30y=189

 

Use the first equation and substitute into the second: 

x=4-y so 60(4-y)+30y=189

240-60y+30y=189

-30y=-51

y=17/10=1 7/10 hours = 1 hour and 42 minutes at 30 mph

(7/10)*60=42

 

Then use the information that it it a total of 4 hours, leaving 2 hours and 18 minutes at 60 mph