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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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07 Mar 2008, 11:43
If it took Carlos ½ hour to cycle from his house to the library yesterday, was the distance that he cycled greater than 6 miles? (1 mile = 5,280 feet)
(1) The average speed at which Carlos cycled from his house to the library yesterday was greater than 16 feet per second. (2) The average speed at which Carlos cycled from his house to the library yesterday was less than 18 feet per second.



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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07 Mar 2008, 12:44
Statement 1: Average Speed > 16 Ft./Sec or 16*60 Feet/Min or 16 * 60 * 60/2 Feet/Half Hour = 480 * 60 Feet/Half Hour = 480 * 60 / 5280 Mile/Half Hour = 5.45 Miles per Half Hour If average speed is just greater than that then Carlos may have covered 5.50 Miles but if average speed is much higher than this then he may have covered much more than 6 miles so insufficient.
Statement 2: Average Speed < 18 Ft/Sec or 540 * 60 / 5280 Miles per Half Hour = 6.14 Miles per Half Hour If average speed is just less than that then Carlos may have covered 6 Miles but if average speed is much lower than this then he may have covered much more less than 6 miles so insufficient.
Combining 1 & 2 is not going to provide any answer either as with 16 Ft/Sec and 18Ft/Sec, he can cover more or less than 6 miles to no definite answer. E



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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07 Mar 2008, 12:46
getting E.
Converting 6 miles/ 30 minutes into feet/second = 17.6 ft/second which doesn't fit individual or combined statements.



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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28 Mar 2008, 22:23
If it took Carlos more than 1/2 hour to cycle from home to office , was the distance he cycled greater than 6 miles ? ( 1 mile = 5280 feet)
1) The average speed at which he cycled from home to office was greater than 16 feet per second. 2) The average speed at which he cycled from home to office was less than 18 feet per second.
A. Statement 1 alone is sufficient B. Statement 2 alone is sufficient C. Both 1 and 2 are needed . D.Either Statement alone is sufficient E.Both Statement 1 & 2 are insufficient



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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29 Mar 2008, 03:01
Average speed = a (feet/hour) The distance = x (feet) The question is : x> 6 miles = 5,280 x 6 = 31, 680 feet?
We have the equation: a * x = 1/2 <=> a = 2x (1)
1. a > 16 feet/second = 16 x 360 feet/hour = 5,760 feet/hour (2) (1)&(2): 2x > 5,760 <=> x > 2,880
2. a < 18 feet/second = 6,480 feet/hour (3) (1)&(3): 2x < 6,480 <=> x < 3,240
So the answer is E (both are insufficient)



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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29 Mar 2008, 03:40
If it took Carlos more than 1/2 hour to cycle from home to office , was the distance he cycled greater than 6 miles ? ( 1 mile = 5280 feet)
1) The average speed at which he cycled from home to office was greater than 16 feet per second. 2) The average speed at which he cycled from home to office was less than 18 feet per second.
Ans is : E
1) he goes in 1 sec : 16 feet+ 1 min : (16*60)+=960+ 30 min: (960*30)+=28800+ it could be greater than six miles or not 2) 16>17<18: let the figure is 17
in the same way we cannot find a decisive result.
so my ans is :E
thanks i think it will help u thinking in simple way.
shobuj



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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29 Mar 2008, 04:01
You're right. Sometimes, I find others have tendency to make an excercise more complicated. Now, so do I.
Thanks for your so clear answer.



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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30 Mar 2008, 00:20
morning, I could not find an explanation to this DS peoblem. Please help!
If it took carlos half an hour to cycle from his house to the library yesterday, was the distance that he cycled greater than 6 miles? (1 mile = 5.28 feet)
1 the average speed at which carlos cycled from his house to the library yesterday was greter than 16 feet per second
2 the average speed at which carlos cycled from his house to the library yesterday was less than 18 feet per second
The answer is E. WHY?



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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30 Mar 2008, 00:40
s>6 miles = 31680 ft, t=30min => v>1056 ft/min (1) v>16ft/s=960ft/min (2) v<18ft/s=1080 ft/min
as u can see v can be <1056 or >1056 from either 1 or 2 > E



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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30 Mar 2008, 01:39
thank you! i've made a mistake 1 mile is 5280 feet AlbertNTN wrote: s>6 miles = 31680 ft, t=30min => v>1056 ft/min (1) v>16ft/s=960ft/min (2) v<18ft/s=1080 ft/min
as u can see v can be <1056 or >1056 from either 1 or 2 > E



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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03 Feb 2009, 16:04
bmiller0731 wrote: If it took Carlos a 1/2 hour to cycle from his house to the library yesterday, was the distance he cycled greater than 6 miles? (1ft = 5,280ft)
1) The average speed at which Carlos cycled from his house to the library yesterday was greater than 16 ft/s 2) The average speed at which Carlos cycled from his house to the library yesterday was less than 18 ft/s D=R*T 1) 16*1800>5,280*6 D>4800 ft insfff 2) D<5,400 ft together 4800<D<5,400 insuff E



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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15 Apr 2009, 05:39
If it took Carlos 1/2 hour to cycle from his house to the library yesterday, was the distance that he cycled greater than 6 miles? (Note: 1 mile=5280 feet.
1) The average speed at which Carlos cycled from his house to the library yesterday was greater than 16 feet per second.
2) The average speed at which Carlos cycled from his house to the library yesterday was greater than 18 feet per second.
This Question was discussed at length; many solved it by converting units. Converting units under pressure (those are ugly numbers!!!) in test day is something I try to avoid. Does anyone can suggest a better approach to take in under 3 min?



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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15 Apr 2009, 14:42
B
1) gives distance greater than (16*60*30)/5280= 5.45 NS could be greater than 6 or less than 6 2) gives distance greater than (18*60*30)/5280=6.14 S



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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17 Apr 2009, 09:41
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GGUY wrote: If it took Carlos 1/2 hour to cycle from his house to the library yesterday, was the distance that he cycled greater than 6 miles? (Note: 1 mile=5280 feet.
1) The average speed at which Carlos cycled from his house to the library yesterday was greater than 16 feet per second.
2) The average speed at which Carlos cycled from his house to the library yesterday was greater than 18 feet per second.
This Question was discussed at length; many solved it by converting units. Converting units under pressure (those are ugly numbers!!!) in test day is something I try to avoid. Does anyone can suggest a better approach to take in under 3 min? For distance > 6 miles and time 1/2 hr the minimum speed needed is 5280*6/60*30 which is more than ~17. So either statement is not sufficient. Therefore I think its E.



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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27 Apr 2009, 00:59
The answer should be B. The calculations are not so ugly.
The question is asking, is the distance greater than 6 miles, ie, greater than 31,680feet (not a hard conversion)?
(1) He travelled at a speed greater than 16 feet/s. If he travelled at 16, he would have covered 28,800feet in 1800 seconds (you just need to multiply 16 with 18again not too time consuming). Clearly this is insufficient.
(2) If he travelled at a speed greater than 18 feet/s, he would have travelled 32,400 milesgreater than 6 miles. Now any higher speed would surely correspond to a distance greater than 6 miles.
Hence B



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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26 Mar 2010, 14:40
I think the answer is (E). Statement 1: Given this situation, Carlos could've pedaled at 16.5ft/sec, which would mark him under 6miles...OR Carlos could've pedaled at 30ft/sec and will definitely put him above 6 miles. So this is insufficient. Statement 2: If Carlos pedaled at 17.9ft/sec, it would mean that the distance was longer than 6 miles. However, he could've been pedaling at 10ft/sec, which means the distance is shorter than 6 miles. Again, insufficient. Taken both together, Carlos would've been pedaling between a rate of 16ft/sec and 18ft/sec, for which there are still numbers in between 16ft/sec and 18ft/sec that would make or break the 6 mile mark. Therefore, E.
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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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26 Mar 2010, 14:49
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changhiskhan wrote: If it took Carlos ½ hour to cycle from his house to the library yesterday, was the distance that he cycled greater than 6 miles? (Note: 1 mile = 5,280 feet)
1) The average speed at which Carlos cycled from his house to the library yesterday was greater than 16 feet per second. 2) The average speed at which Carlos cycled from this house to the library yesterday was less than 18 feet per second.
Thanks in advance! options are in feet per sec. so to get 6 miles in 1/2 hrs lets find out teh avg speed(x feet per sec) x * 60 * 30 / 5280 = 6 x = 17.6 .. so avg speed has to be greater than 17.6 for the distance to be greater than 6 miles st 1 ) not sufficient st 2) not sufficient combining also cannot tell E



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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27 Mar 2010, 08:24
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changhiskhan wrote: If it took Carlos ½ hour to cycle from his house to the library yesterday, was the distance that he cycled greater than 6 miles? (Note: 1 mile = 5,280 feet)
1) The average speed at which Carlos cycled from his house to the library yesterday was greater than 16 feet per second. 2) The average speed at which Carlos cycled from this house to the library yesterday was less than 18 feet per second.
Thanks in advance! with speed 16ft /sec in 1/2 hr it travelled 28800 ft or 60/11 miles < 6 miles there can be values which satisfies both condition hence insufficient. same for speed 18 ft/sec it is also insuffcient. Both also insufficient, hence E.



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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02 Apr 2010, 00:48
The answer is E in the original question at GMAT prep (Because Answer (2) says if the speed is LESS than 18 feet/second and NOT more.
How the question is stated here however B is correct.
I have a slightly different approach, which might be faster. I took the question stem and calculated what the necessary speed would be to travel 6 miles in 1/2 hour. 6 miles x 5280 feet = 31680 feet 1/2 hour = 30 minutes x 60 seconds = 1800 seconds
Now I divided 31680 by 1800 which is 17,...
This means that answer (1) might or might not be greater than the necessary 17,... Answer (2) might or might not be lower than 17,...



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Re: If it took Carlos 1/2 hour to cycle from his house to the [#permalink]
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20 Apr 2010, 12:34
the answer has to be B rephrasing the question you get; "is the rate greater than 17.6ft/sec?" clearly B is sufficient.
answer would be E if the condition in statement 2 would have been less than 18ft/sec.




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