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# Airplanes A and B traveled the same 360-mile route

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Airplanes A and B traveled the same 360-mile route  [#permalink]

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02 Mar 2012, 09:28
00:00

Difficulty:

5% (low)

Question Stats:

91% (01:11) correct 9% (00:43) wrong based on 137 sessions

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Airplanes A and B traveled the same 360-mile route. If airplane A took 2 hours and airplane B traveled at an average speed that was $$\frac{1}{3}$$ slower than the average speed of airplane A, how many hours did it take airplane B to travel the route?

(A) 2

(B) $$2\frac{1}{3}$$

(C) $$2\frac{1}{2}$$

(D) $$2\frac{2}{3}$$

(E) 3

I agree with the OA.
However, something that I don't understand is why cannot analyze it in this way:
The question says that airplane B traveled at an average speed that was $$\frac{1}{3}$$ slower than the average speed of airplane A, right?
The OE says that, based on this info, that airplane A travels at 180 mph, so airplane B travels at 120 mph (1/3 slower).
Why cannot "1/3 slower" mean this?
A ---- 180 miles / 1 hour
B ---- 180 miles /[(4/3)*1hour]

Source: http://www.gmathacks.com

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Re: Airplanes A and B traveled the same 360-mile route  [#permalink]

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02 Mar 2012, 09:47
1
metallicafan wrote:
Airplanes A and B traveled the same 360-mile route. If airplane A took 2 hours and airplane B traveled at an average speed that was $$\frac{1}{3}$$ slower than the average speed of airplane A, how many hours did it take airplane B to travel the route?
(A) 2
(B) $$2\frac{1}{3}$$
(C) $$2\frac{1}{2}$$
(D) $$2\frac{2}{3}$$
(E) 3

I agree with the OA.
However, something that I don't understand is why cannot analyze it in this way:
The question says that airplane B traveled at an average speed that was $$\frac{1}{3}$$ slower than the average speed of airplane A, right?
The OE says that, based on this info, that airplane A travels at 180 mph, so airplane B travels at 120 mph (1/3 slower).
Why cannot "1/3 slower" mean this?
A ---- 180 miles / 1 hour
B ---- 180 miles /[(4/3)*1hour]

Source: http://www.gmathacks.com

The red part should be 3/2.

I'd approach this question in different manner and hope that it helps you to understand the question better.

Since B traveled at an average speed that was $$\frac{1}{3}$$ slower than the average speed of airplane A, then the speed of B was $$\frac{2}{3}$$ of that of A ($$x-\frac{1}{3}x=\frac{2}{3}x$$). So, airplane B would need $$\frac{3}{2}$$ times more time to cover the same distance: $$2*\frac{3}{2}=3$$ hours. That's because time*rate=distance, so if you decrease rate 2/3 times you'll need 3/2 times as many hours to cover the same distance.

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Re: Airplanes A and B traveled the same 360-mile route  [#permalink]

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31 Dec 2013, 10:41
metallicafan wrote:
Airplanes A and B traveled the same 360-mile route. If airplane A took 2 hours and airplane B traveled at an average speed that was $$\frac{1}{3}$$ slower than the average speed of airplane A, how many hours did it take airplane B to travel the route?

(A) 2

(B) $$2\frac{1}{3}$$

(C) $$2\frac{1}{2}$$

(D) $$2\frac{2}{3}$$

(E) 3

I agree with the OA.
However, something that I don't understand is why cannot analyze it in this way:
The question says that airplane B traveled at an average speed that was $$\frac{1}{3}$$ slower than the average speed of airplane A, right?
The OE says that, based on this info, that airplane A travels at 180 mph, so airplane B travels at 120 mph (1/3 slower).
Why cannot "1/3 slower" mean this?
A ---- 180 miles / 1 hour
B ---- 180 miles /[(4/3)*1hour]

Source: http://www.gmathacks.com

Easy question

A traveled at 180mph

2/3*180 = 120mph

Hence B made the trip in 360/120 = 3 hours

Or recall that as distance is constant, then B will need 3/2 as much time as A to cover same distance

So it will give 3 as well
Hope it helps
Cheers!
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Airplanes A and B traveled the same 360-mile route  [#permalink]

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22 Nov 2017, 20:09
1
Hi All,

If you don't realize how that relationship between speed and time applies in these types of questions, then you can still answer this question with some basic arithmetic.

We're told that Airplane A traveled a 360-mile route in 2 hours. Thus, it traveled at 360/2 = 180 miles per hour.

We're also told that Airplane B traveled the SAME distance at an average speed that was 1/3 SLOWER than the average speed of airplane A. One third of 180 is 60, so Airplane B traveled at 180 - 60 = 120 miles per hour.

We're asked for the number of hours that it took Airplane B to travel the route....
Distance = (Rate)(Time)
360 miles = (120 mi/hour)(T)
360/120 = T
3 hours = T

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Airplanes A and B traveled the same 360-mile route &nbs [#permalink] 22 Nov 2017, 20:09
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