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by HPengineer » Mon Aug 23, 2010 9:57 am
If 75 percent of the guests at a certain banquet ordered dessert, what percent of the guests ordered coffee?
(1) 60 percent of the guests who ordered dessert also ordered coffee.
(2) 90 percent of the guests who ordered coffee also ordered dessert.

Normally i use the table to solve these overlapping sets problems... However the second statement is troubling me. How would this statement fit into an overlapping sets table?
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Source: — Data Sufficiency |

by Gurpinder » Mon Aug 23, 2010 12:48 pm
HPengineer wrote:If 75 percent of the guests at a certain banquet ordered dessert, what percent of the guests ordered coffee?
(1) 60 percent of the guests who ordered dessert also ordered coffee.
(2) 90 percent of the guests who ordered coffee also ordered dessert.

Normally i use the table to solve these overlapping sets problems... However the second statement is troubling me. How would this statement fit into an overlapping sets table?

Hmm.....I agree. Aren't (1) and (2) saying that same thing? Xperts help!!
"Do not confuse motion and progress. A rocking horse keeps moving but does not make any progress."
- Alfred A. Montapert, Philosopher.
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by gb » Mon Aug 23, 2010 2:41 pm
HPengineer wrote:If 75 percent of the guests at a certain banquet ordered dessert, what percent of the guests ordered coffee?
(1) 60 percent of the guests who ordered dessert also ordered coffee.
(2) 90 percent of the guests who ordered coffee also ordered dessert.

Normally i use the table to solve these overlapping sets problems... However the second statement is troubling me. How would this statement fit into an overlapping sets table?
--

For option C ..I think this is what is said in the question -

60 % of (75% of total guest ) = 90 % of Coffee
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by missrochelle » Tue Aug 31, 2010 4:12 pm
I'm having trouble with this one too.....we dont know the total guests...so how can we compute coffee?

For these overlapping sets - when do you use real #s vs just percentages?

This problem seems to flip flop between the two.

For example, they define statement 1 --- dessert&coffee = 60% of 75. But the question stem says 75% of guests? That's not a number! Makes it hard to come up with a surefire strategy for the overlapping sets questions....they word them all so differently.
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by goyalsau » Tue Aug 31, 2010 9:18 pm
If 75 percent of the guests at a certain banquet ordered dessert, what percent of the guests ordered coffee?
(1) 60 percent of the guests who ordered dessert also ordered coffee.
(2) 90 percent of the guests who ordered coffee also ordered dessert.


According to me the answer is C.

Now lets see why i think like that.

From the question : if there are total of 100 guest , out of those 75 ordered dessert.

By First statement : 60% of 75. 45 ordered coffee as well. But we don't know any thing about group which only ordered coffee so , " not sufficient "

By second Statement : We don't know any thing about the percent of people who ordered coffee so can't make any thing out of this statement alone. we know 45 is 90 by the second statement.
so 100 percent is 50.

its C.

But if we consider both the statement together
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