Magoosh
David drove to work at an average (arithmetic mean) speed of \(45\) miles per hour. After work, David drove home at an average speed of 60 miles per hour. If David spent a total of 2 hours commuting to and from work, how many miles does David drive to work?
A. \(48\)
B. \(\frac{256}{5}\)
C. \(\frac{360}{7}\)
D. \(\frac{105}{2}\)
E. \(\frac{160}{3}\)
OA C
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David drove to work at an average (arithmetic mean) speed of
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Brent@GMATPrepNow
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Let's start with a "word equation"AAPL wrote:Magoosh
David drove to work at an average (arithmetic mean) speed of 45 miles per hour. After work, David drove home at an average speed of 60 miles per hour. If David spent a total of 2 hours commuting to and from work, how many miles does David drive to work?
A. \(48\)
B. \(\frac{256}{5}\)
C. \(\frac{360}{7}\)
D. \(\frac{105}{2}\)
E. \(\frac{160}{3}\)
OA C
We can write: (David's travel time TO work) + (David's travel time FROM work) = 2 hours
time = distance/speed
Let d = the distance each way
We can write: d/45 + d/60 = 2
To eliminate the fractions, multiply both sides by 180, the LCM of 45 and 60
We get: 4d + 3d = 360
Simplify: 7d = 360
Solve: d = 360/7
Answer: C
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Scott@TargetTestPrep
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We can create the equation for the time:AAPL wrote:Magoosh
David drove to work at an average (arithmetic mean) speed of \(45\) miles per hour. After work, David drove home at an average speed of 60 miles per hour. If David spent a total of 2 hours commuting to and from work, how many miles does David drive to work?
A. \(48\)
B. \(\frac{256}{5}\)
C. \(\frac{360}{7}\)
D. \(\frac{105}{2}\)
E. \(\frac{160}{3}\)
OA C
d/45 + d/60 = 2
Multiplying by 180, we have:
4d + 3d = 360
7d = 360
d = 360/7
Answer: C
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