SOLUTION: chad drove three times as fast as katy pedaled. In fact chad drove 90 miles in 2 hrs less than it took katy to pedal 40 miles how fast did each of them travel? How long did they

Algebra ->  Test -> SOLUTION: chad drove three times as fast as katy pedaled. In fact chad drove 90 miles in 2 hrs less than it took katy to pedal 40 miles how fast did each of them travel? How long did they       Log On


   

Question 328422: chad drove three times as fast as katy pedaled. In fact chad drove 90 miles in 2 hrs less than it took katy to pedal 40 miles how fast did each of them travel? How long did they travel?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
given:
Katy:
d+=+r%2At
40+=+r%5Bk%5D%2At%5Bk%5D
Chad:
90+=+3r%5Bk%5D%2A%28t%5Bk%5D+-+2%29
90+=+3%2Ar%5Bk%5D%2At%5Bk%5D+-+6r%5Bk%5D
By substitution:
90+=+3%2A40+-+6r%5Bk%5D
6r%5Bk%5D+=+120+-+90
6r%5Bk%5D+=+30
r%5Bk%5D+=+5 mi/hr
and
r%5Bc%5D+=+3r%5Bk%5D
r%5Bc%5D+=+15 mi/hr
How long did they travel?
t%5Bk%5D+=+40%2Fr%5Bk%5D
t%5Bk%5D+=+40%2F5
t%5Bk%5D+=+8 hrs
and
t%5Bc%5D+=+90%2Fr%5Bc%5D
t%5Bc%5D+=+90%2F15
t%5Bc%5D+=+6 hrs
Katy traveled for 8 hrs
Chad traveled for 6 hrs