Total time with variable speeds = (x+5)/60
Total time with constant Speed = (x/)/60
difference = 1/12 ~ 8.5%
as you see, just getting started
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Source: Beat The GMAT — Problem Solving |
Answer "A"?
Total time with variable speeds = (x+5)/60
Total time with constant Speed = (x/)/60
difference = 1/12 ~ 8.5%
as you see, just getting started
Total time with variable speeds = (x+5)/60
Total time with constant Speed = (x/)/60
difference = 1/12 ~ 8.5%
as you see, just getting started
The answer is indeed E.gxliu wrote:Answer is actually E.
Variable time = (x+5)/60
Constant time = x/60
We have to find out the percentage difference, the question already tells us that variable time is greater.
[(x+5)/60 - x/60] / x/60 => (5/x) * 100 = 500%/x
Kindly correct me if I have missed anything.
Thanks,
-
AleksandrM
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How come you add 5, whereas you should subtract the five miles already traveled from the entire distance x, to give you the remainding distance that is traveled at 60 m/hparallel_chase wrote:The answer is indeed E.gxliu wrote:Answer is actually E.
Variable time = (x+5)/60
Constant time = x/60
We have to find out the percentage difference, the question already tells us that variable time is greater.
[(x+5)/60 - x/60] / x/60 => (5/x) * 100 = 500%/x
Kindly correct me if I have missed anything.
Thanks,
I set it up as
First 5 miles:
rate = 30 and distance is 5 miles
The remaining trip:
rate = 60 and distance is x - 5
The second situation:
rate = 60 for the entire trip x.
Well here it is:AleksandrM wrote:parallel_chase wrote:The answer is indeed E.gxliu wrote:Answer is actually E.
Variable time = (x+5)/60
Constant time = x/60
We have to find out the percentage difference, the question already tells us that variable time is greater.
[(x+5)/60 - x/60] / x/60 => (5/x) * 100 = 500%/x
Kindly correct me if I have missed anything.
Thanks,
How come you add 5, whereas you should subtract the five miles already traveled from the entire distance x, to give you the remainding distance that is traveled at 60 m/h
I set it up as
First 5 miles:
rate = 30 and distance is 5 miles
The remaining trip:
rate = 60 and distance is x - 5
The second situation:
rate = 60 for the entire trip x.
In order to find the percentage difference you have to compare the complete distances.
for 5 miles the rate is 30 = 5/30
for x-5 miles the rate is 60 = x-5/60
add both the rates to find the rate for the complete distance i.e. x
5/30 + (x-5)/60 = (10+x-5)/60 = (x+5)/60
second situation
x/60
now find the percentage difference.
Let me know if you still have any questions.
5/30 + (x-5)/60 = (10+x-5)/60 = (x+5)/60
quick question-how did you get (10+x-5)/60 to (x+5)/60
thanks
quick question-how did you get (10+x-5)/60 to (x+5)/60
thanks
10-5 = 5notgoodinmath wrote:5/30 + (x-5)/60 = (10+x-5)/60 = (x+5)/60
quick question-how did you get (10+x-5)/60 to (x+5)/60
thanks
we already have x as a variable
therefore,
(10-5+x)/60 => (x+5)/60
Hope its clear now.
An easier way to solve this is just plug in a number. If we say x is 10 miles,
It would have been 10 min. + 5 min. = total of 15 min.
If it had been 60 mph the entire time it would be = total of 10 min.
15 is 50% greater than 10.
Now all we have to do is put 10 in for x in each of the options and when we get 50 that's the answer.
It would have been 10 min. + 5 min. = total of 15 min.
If it had been 60 mph the entire time it would be = total of 10 min.
15 is 50% greater than 10.
Now all we have to do is put 10 in for x in each of the options and when we get 50 that's the answer.
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