Edwin is planning to drive from Boston to New Orleans. By what percent : Data Sufficiency (DS)

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Edwin is planning to drive from Boston to New Orleans. By what percent

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Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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06 Oct 2014, 08:53

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Difficulty:

45% (medium)

Question Stats:

65% (01:33) correct

35% (01:47) wrong

based on 757 sessions

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Tough and Tricky questions: Distance/Rate .

Spoiler: OA

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Re: Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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04 Jul 2016, 11:21

Edwin is planning to drive from Boston to New Orleans. By what percent would his travel time be reduced if Edwin decides to split the driving time equally with his friend George, instead of making the trip alone?

(1) The driving distance from Boston to New Orleans is 1500 miles.
(2) George’s driving speed is 1.5 times Edwin’s driving speed.

Statement 1 : Does not tell us either Edwin'speed or George's. Hence we cannot calculate time taken in any scenario. INSUFFICIENT

Statement 2 : Let distance be d

Time taken originally = d/s

Now in second scenario Edwin drives k miles and George drives d-k miles

Therefore time taken = k/s + d-k/(1.5s)

k/s = (d-k) / (1.5)s ... Given

d=2.5k

Therefore original time taken = 2.5k /s

New time taken = k/s + (1.5k/1.5s)

= (2k)/s

Reduction is 0.5 k/s

Therefore percent reduction is 20%

SUFFICIENT
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Re: Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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11 Oct 2014, 03:58

Bunuel wrote:

Tough and Tricky questions: Distance/Rate .

B.

1) only distance is given, speed/time is not given so insufficient.

2) let edwin's speed be x. --> george's speed becomes 1.5x
so when he travels alone, he must have taken d/x amount of time
now when he splits the driving time equally with george, then lets assume he drove for k miles
=> k/x = (d-k)/1.5x
=> 2.5k = d

earlier he travelled for 2.5k/x hours, now he travels for k/x hours. so time reduction rate can be calculated. hence, sufficient.
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Re: Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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25 Jan 2015, 03:08

Bunuel wrote:

Tough and Tricky questions: Distance/Rate .

I got this question on Mgmat too.
Time was less so i just did it very fast.
A- We have to see the time but only distance given. Cant take any thing out of it. So A and D gone.
B- Driving speed relation given and we know from question stem time is split equally. Bingo Time and speed relation can be established and there by the reduced time percent.
So answer is B

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Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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27 Aug 2015, 06:39

A is not sufficient as the distance alone does not tell us the respective speeds of the two.

B alone is sufficient because ratio os speed also gives a ratio of time, as the distance is constant

When distance is constant, Speed is inversely proportional to time
When speed is constant, Distance is proportional to time
When time is constant, distance is proportional to spee.
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Re: Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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28 Nov 2016, 09:23

rishi02 - You are taking both Edwin and George's time into consideration while calculating the reduction, whereas only Edwin's Driving time reduction is asked. Earlier Edwin was taking 2.5k/s time alone for driving and after taking help from George, his driving time has reduced to k/s. So, percentage of Edwin's driving time reduction can be calculated.
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Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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23 Jun 2018, 08:26

thefibonacci wrote:

Bunuel wrote:

Tough and Tricky questions: Distance/Rate .

The question asks what is the reduction in travel time as a result of the drive being split with George who from statement 2 we know is a faster driver. But the reduction should be set up as comparing it between him driving alone (2.5k/x) vs his total time by splitting the drive with George, not just his share of it; in the 2nd scenario, his travel time would include the period where George drives too, wouldn't it?
I'm not sure if I'm right, please let me know Bunuel ?

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Re: Edwin is planning to drive from Boston to New Orleans. By what percent [#permalink]

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19 Aug 2018, 00:05

Statement 1 : Does not tell us either Edwin'speed or George's. Hence we cannot calculate time taken in any scenario. INSUFFICIENT
Statement 2: Tells us the speed rate of edwin and george.
It's already given that both of them drove for an equal amount of time , so u can find the % amount of time reduced irrespective of the distances because of the reasons provided.

So, statement 2 alone is sufficient