Your aunt and uncle have been visiting at your home. Five minutes after they drive away, you realize that they forgot their luggage. You happen to know that they drive slowly, so you get in your car and drive to catch up with them. Your average speed is 10 miles an hour faster than their average speed, and you catch up with them in 25 minutes. How fast did you drive?
It says to use the following verbal model:
your speed = their speed + 10 miles
your speed x your time in hours = their speed x their time in hours
The answer in the back of the book says it's 60 mph. =/
2007-10-01 13:18:03 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
The distance that you and your aunt/uncle cover are exactly the same. Since distance = rate * time,
your speed * your travel time = their speed * their travel time
(v + 10) mph * (5/12) h = (v) mph * (1/2) h
5 * (v + 10) = 6 v
aunt/uncle avg. speed = v = 50 mph
your speed = v + 10 = 60 mph
2007-10-01 13:53:40 · answer #1 · answered by The K-Factor 3 · 0⤊ 0⤋