SOLUTION: the time it takes to travel a certain distance varies inversely as the rate of speed. if it takes lena 40 minutes to drive to work when she drives at 45 miles per hour, how long wi

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Question 273792: the time it takes to travel a certain distance varies inversely as the rate of speed. if it takes lena 40 minutes to drive to work when she drives at 45 miles per hour, how long will it take her to drive the same distance if she drives at 50 miles per hour?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
the way to do it is with a "constant of proportionality"
which is usually k
given:
40+=+k%2A%281%2F45%29
k+=+45%2A40
k+=+1800
---------------
Using 50 mi/hr instead of
45 mi/hr
t+=+k%2A%281%2F50%29
t+=+1800%2A%281%2F50%29
t+=+36 min