How many buses are required to transport 175 students to the museum?
1. No two buses have the same carrying capacity
2. The average capactiy of a bus is 55 students
I got this seemingly easy DS question wrong. My line of thinking was this:
1. Insufficient
2. 4x55 > 175 so kind of sufficient. However you could have theoreitcal buses that have a max capacity of 1 student, and another with a max capactiy of 109 students. Then you could have 2 additional buses with a capacity of 2 and 108 respectively. With these four buses you would only need the 109 and 108 capacity buses to transport the students. However I realize without the 1 and 2 capacity buses included, the average capacity of the two being used jumps up to 217/2.
I guess my question is when to know when they are asking something super simple vs something that seems super simple but is a 700+ question? Any suggestions and insight would be helpful
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Stuart@KaplanGMAT
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Hi!
What's the source of this question? I ask because there's important wording missing from the statements in order for (B) to be the correct answer.
You're 100% right in your counter-argument to (2) being sufficient. For (2) to be sufficient alone, it should read:
What's the source of this question? I ask because there's important wording missing from the statements in order for (B) to be the correct answer.
You're 100% right in your counter-argument to (2) being sufficient. For (2) to be sufficient alone, it should read:
Both statements refer to buses in general, which is 100% unhelpful to solve the question; each should refer to the buses actually used (unless the answer is supposed to be (E)).(2) The average capacity of the buses used is 55 students.
parkman wrote:How many buses are required to transport 175 students to the museum?
1. No two buses have the same carrying capacity
2. The average capactiy of a bus is 55 students
I got this seemingly easy DS question wrong. My line of thinking was this:
1. Insufficient
2. 4x55 > 175 so kind of sufficient. However you could have theoreitcal buses that have a max capacity of 1 student, and another with a max capactiy of 109 students. Then you could have 2 additional buses with a capacity of 2 and 108 respectively. With these four buses you would only need the 109 and 108 capacity buses to transport the students. However I realize without the 1 and 2 capacity buses included, the average capacity of the two being used jumps up to 117/2.
I guess my question is when to know when they are asking something super simple vs something that seems super simple but is a 700+ question? Any suggestions and insight would be helpful
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
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The source is from Practice Test 2 from "Master the GMAT 2012" from Peterson's Publishing. I double checked and I copied the question verbatim.
I find it incredibly encouraging you also found the wording of this question to be misleading/confusing. Makes me hopeful I am headed in the right direction
I find it incredibly encouraging you also found the wording of this question to be misleading/confusing. Makes me hopeful I am headed in the right direction
Last edited by parkman on Mon Apr 18, 2011 12:08 pm, edited 1 time in total.
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Ian Stewart
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Yes, I agree with Stuart - this question makes very little sense. The wording is so imprecise the question is really testing whether you can guess what the question designer was thinking, and not whether you have any mathematical ability.parkman wrote:How many buses are required to transport 175 students to the museum?
1. No two buses have the same carrying capacity
2. The average capactiy of a bus is 55 students
If you're studying from unofficial sources, some questions are only 'hard' because the person writing them needed a better editor. As for official questions, some of the seemingly simple ones can also be tricky, often because it's possible you won't recognize the implications of the information provided. Q123 in the DS section of OG12 (the 'stamps question') is one example; many people simply count equations and unknowns, ignoring how important it is that the numbers of stamps of each type must be integers. As you work through other official questions, you'll see a few more examples, but you won't ever find official questions 'tricky' because they are open to various legitimate interpretations.parkman wrote: I guess my question is when to know when they are asking something super simple vs something that seems super simple but is a 700+ question? Any suggestions and insight would be helpful
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com
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My copy of the OG 12th edition came in the mail today so hopefully I won't come across this type of problem again. I bought the first book that had GMAT in bold print on the cover. I didn't realize the gravity of my error until I found these forums. Thanks for the clarification!
