Trick Question?

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Trick Question?

by Rastis » Fri May 08, 2015 12:12 pm
It takes Amy between 6 and 7 minutes to grill a steak, and she can only grill one steak at a time. She does not need to take breaks between steaks. Can Amy finish grilling all the steaks needed for her party before her guests arrive?

(1) Amy needs to grill four steaks for her party.

(2) Amy's guests will arrive in 25 to 30 minutes.



I believe the answer is C but they say it's E. She finishes grilling the steaks between 24 and 28 mins, which would be before her guests are scheduled to arrive.

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by GMATGuruNY » Fri May 08, 2015 1:01 pm
Rastis wrote:It takes Amy between 6 and 7 minutes to grill a steak, and she can only grill one steak at a time. She does not need to take breaks between steaks. Can Amy finish grilling all the steaks needed for her party before her guests arrive?

(1) Amy needs to grill four steaks for her party.

(2) Amy's guests will arrive in 25 to 30 minutes.
The following cases satisfy both statements.

Worst-case scenario: GREATEST possible time per steak + EARLIEST possible arrival time.
Greatest possible time for 4 steaks = 7*4 = 28 minutes.
Earliest possible arrival time = 25 minutes.
In this case, the steaks are not grilled on time.

Best-case scenario: LEAST possible time per steak + LATEST possible arrival time.
Least possible time for 4 steaks = 6*4 = 24 minutes.
Latest possible arrival time = 30 minutes.
In this case, the steaks are grilled on time.

Thus, the two statements combined are INSUFFICIENT.

The correct answer is E.
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by Rastis » Fri May 08, 2015 1:12 pm
Mitch,

But the question asks if the steaks can be grilled before her guests arrive, not if they are grill between 25-30 mins. If the steaks can be finished either at 24 mins or 28 mins, they are still finished before the guests arrive.

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by AdamMac » Fri May 08, 2015 8:15 pm
Hi rastis,

But not necessarily. That's why it's still E.

With the combined information, there's still a chance that if takes 28 minutes to grill the steaks, and the people arrive in 25 minutes, the steaks wouldn't be ready.

Since we can't say completely sufficient, it has to be E. Does that makes sense?

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by Rastis » Sat May 09, 2015 7:10 am
That's much clearer! Thanks!