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When you buy a wrap from a certain store, you must select at

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When you buy a wrap from a certain store, you must select at

by Max@Math Revolution » Wed Mar 21, 2018 11:45 pm
[GMAT math practice question]

When you buy a wrap from a certain store, you must select at least one of the three kinds of meat (beef, pork and fish), and one of lettuce, spinach and cucumber. You can also add one of oriental sauce, spicy mayo and sesame soy sauce. How many kinds of wraps can you buy?

A. 6
B. 9
C. 12
D. 18
E. 27
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by Max@Math Revolution » Sun Mar 25, 2018 5:14 pm
=>
There are three ways to choose one meat (beef, pork or fish), three ways to choose one vegetable (lettuce, spinach or cucumber), and 3 ways to choose one sauce (oriental sauce, spicy mayo or sesame soy sauce).
So, the total number of different wraps that can be bought is

3*3*3 = 27.

Therefore, E is the answer.

Answer: E
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by swerve » Mon Mar 26, 2018 7:38 am
The question says you must select at least one of 3 meats, which mean you can select 1 meat or 2 or 3. The question also says that you can (not must) add one sauce, which means you can add 0 sauce or 1 sauce.

Number of ways to select 1 meat: 3C3 = 3
Number of ways to select 2 meats: 3C2 = 3
Number of ways to select 3 meats: 3C3 = 1

The total number of ways to select meat = 3 + 3 + 1 = 7.

Number of ways to select 1 veggie: 3
Number of ways to select 0 sauce OR 1 sauce: 1 + 3 = 4.

# of different wraps = (Total number of ways to select meat)*(Number of ways to select 1 veggie)*(Number of ways to select 0 sauce OR 1 sauce) = 7*3*4 = 84.

Where is the mistake?

Regards!
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