SOLUTION: On Monday, Roger drove to work in 45 minutes. On Tuesday he averaged 12 miles per hour more, and it took him 9 minutes less to get to work. How far does he travel to work?

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Question 270793: On Monday, Roger drove to work in 45 minutes. On Tuesday he averaged 12 miles per hour more, and it took him 9 minutes less to get to work. How far does he travel to work?
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
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On Monday, Roger drove to work in 45 minutes. On Tuesday he averaged 12 miles per hour more, and it took him 9 minutes less to get to work. How far does he travel to work?
:
Change 45 min: 45/60 .75 hr
Change 9 min: 9/60 = .15 hr
:
Let d = distance to work
we know
Monday it took .75 hrs to get to work
Tuesday, (.75-.15) = .6 hrs to get to work
:
Write a speed equation(Speed = dist/time)
:
Tuesday speed - Monday speed = 12 mph
d%2F.6 - d%2F.75 = 12
Multiply by 3, to clear the denominators, results
5d - 4d = 3(12)
d = 36 miles to work
;
:
See if that is true
Find the difference in speed
36/.6 = 60
36/.75 =48 mph
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differ = 12