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There are 30 cars in my building's parking lot. All of the cars are red or white, and a car can have either 2 doors or 4 doors. 1/3 of them are red, 50% of them are 4-door, and 8 of them are 2-door and white. How many of the cars are 4-door and red?

Guest Aug 25, 2018
 #1
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Make a two-way table as follows:
                                            RED                            WHITE
2-DOOR                               7                                        8

4-DOOR                               3                                      12
TOTALS                               10                                     20

 

So, it looks like you have 3 cars that are red and have 4 doors.

Guest Aug 25, 2018
 #2
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Thanks, guest....here's another way

 

(1/3) are red  =  30 *1/3  = 10 are red

So...20  are white

50% are 4 door   = 15  are 4 door

So    ....15 are 2 door

8 are 2 door  and white.....so 12 are 4 door and white  since we have 20 white total

And since 15 are 4 door  and 12 of these are white...then 3 must be 4 door and red

 

 

cool cool cool

CPhill  Aug 25, 2018

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