SOLUTION: communiting to work. 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 t
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Question 83836This question is from textbook elementary Algebra
: communiting to work. 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? This question is from textbook elementary Algebra
You can put this solution on YOUR website! 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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If we find the speed, it's a simple matter to find the distance.
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Let s = speed driven on Monday
Then (s+12) = speed driven on Tuesday
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Change minutes to hours (our speed is in mph)
45 min = 45/60 = .75 hr
9 min faster = 36 min = 36/60 = .6 hrs
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We can assume that the two trips were the same distance
From this fact we can make a simple distance equation:
Distance = time * speed
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Monday dist = Tuesday dist
.75s = .6(s+12)
.75s = .6(s+12)
.75s = .6s + 7.2
.75s - .6s = 7.2
.15s = 7.2
s = 7.2/.15
s = 48 mph on Monday
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48 + 12 = 60 mph on Tuesday
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Find distance using 48 mph for 45 min (.75 hrs)
48 * .75 = 36 miles
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Check our solution by using 60 mph for 36 min (9 min faster) (.6 hr)
60 * .6 = 36 miles also
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