To solve d=rt problems, just plug in the numbers. Distance = Rate * Time
where distance is the distance traveled, rate is the average speed during
the period, and time is how long it took to reach point b.


ex) Danny drove his car at an average speed of 75mph for 2 and a half
hours. How far did he travel during that time?


We know he traveled at 75mph for 2.5 hours. Plug in these numbers to
the equation d=rt. d=75mph*2.5hours

distance traveled = 187.5 miles.

ex) A train traveled 200 miles in 3 hours. What was its average speed
during the trip?

Plug in to the equation and solve for r...d=rt 200=r (3)

r= 200/3...r= 66.67mph

ex) Haley has to be in LA in 2 hours. If she is 150 miles away, what
speed must she average to arrive on time?

d=rt...    150=r (2)

r= 150/2
r= 75mph


 
Practice:
 
1) A speed boat travels up a river at 50mph. After 30 minutes, how far will it have gone?
 
 
 
2) A Crazy plane is flying at 1750mph. It does so for 1.7 hours. How far did it travel during that time?
 
 
3) If a subway train’s average speed is 80mph, how long will it take it to travel 500 miles?
 
 
4) A man in his car drove 1200 miles. His average speed during the drive was 60mph. 
    How long did it take him to drive that far?