SOLUTION: Red Riding Hood drives the 432 miles to go Grandmother�s house in 1 hour less than it takes the Wolf to drive the same route. Her average speed is 6 mph faster than the Wolf�s ave

Question 632407: Red Riding Hood drives the 432 miles to go Grandmother�s house in 1 hour less than it takes the Wolf to drive the same route. Her average speed is 6 mph faster than the Wolf�s average speed. How fast does Red Riding Hood drive?
Found 2 solutions by josmiceli, solver91311:
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Let = the Wolf's time to get there in hours
Let = Wolf's average speed in mi/hr
given:
RRH's equation:
(1)
Wolf's equation:
(2)
--------------
(1)
and
(2) t = 432/s }}}
-------------
Substitute (2) into (1)
(1)
Multiply both sides by
(1)
(1)
Use quadratic equation

( ignore the negative square root )

RRH's speed was 48 mi/hr
check answer:
(2)
(2)
(2) hrs
and
(1)
(1)
(1)
(1)
(1)
OK
Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!

Let represent RRH's rate, so must represent BBW's rate. Let represent the time it took RRH to make the trip and must then represent BBW's time.

Starting with Distance Equals Rate Times Time, we can easily derive that Distance divided by Rate equals Time, so RRH's trip is described by:

And BBW's trip:

A little algebra music, Sammy (and I leave it as an exercise for the student to verify)

Now that we have two different expressions in that are both equal to , set them equal to each other:

Cross-multiply:

Simplify to standard quadratic form:

Solve for the positive root, then calculate

John

My calculator said it, I believe it, that settles it

RELATED QUESTIONS
Red Riding Hood drives 432 miles to Grandmother's house in one hour less than it takes... (answered by lwsshak3)
Little Red Riding Hood, in order to make it to Grandma's house and back home in time for... (answered by macston)
Rob drives 550 miles home in one hour less than it takes Mary to drive the same route.... (answered by Paul)
Two brothers leave from the same location, one in a car and the other on a bicycle, to... (answered by josmiceli)
Little red riding hood rides to grandmas house at 20 mph . She goes back on the same path (answered by josmiceli,Alan3354)
okay. So i'm very confused and stuck on this problem. i really need help. here is the... (answered by ankor@dixie-net.com,nerdybill)
Beverly can drive 600 miles in the same time as it takes suzan to drive 500 miles. if... (answered by ewatrrr)
don can drive 100 miles to work in the same amount of time that it takes him to drive 60... (answered by jorel555)
Richard's average driving speed is 4 miles per hour faster than Kirk's. In the same... (answered by Paul)