Mo2men wrote:
kiran120680 wrote:
Seven water stations were set up at equal intervals along the 42-kilometer route of a marathon, with the last water station at the finish point. If James maintained a uniform running speed throughout the marathon, did not turn back at any time and reached the finish line, in how much time did he run the marathon? [Note: Assume that the first station does not coincide with the starting point]
I. 40 minutes after the start of the marathon, James was 4 kilometers away from the second water station
II. 20 minutes before reaching the finish point, James was 20 kilometers away from the third water station
Dear
GMATGuruNYCould you please help with this question?
Does not the assumption noted above [Note: Assume that the first station does not coincide with the starting point] imply that we have distance covered before water station 1 and should be counted in the distance covered by the runner?
My approach would be the same as Aviddreamer's.
The 7 water stations are equally spaced along the 42km route.
No water station is located at the start of the route.
Water Station 7 is located at the end of the route.
Thus, the following figure is implied:
Attachment:
water stations.png [ 26.13 KiB | Viewed 4467 times ]
If we know James' rate, we can calculate his time to complete the 42km marathon.
Statement 1:
Water Station 2 is located at the 12km mark.
Since James is 4km away from Station 2, the distance traveled in 40 minutes could be 12-4=8km or 12+4=16km.
Thus, two different rates are possible.
INSUFFICIENT.
Statement 2:
Water Station 3 is located at the 18km mark.
For James to be 20km away, the distance traveled must be 18+20 = 38km.
Implication:
In the last 20 minutes, James must travel the remaining 4km of the 42km marathon, yielding the following rate:
\(\frac{4-km}{20-minutes}\)
SUFFICIENT.
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