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Comment on Cable TV and Kitchenette
Why do all that when you can
That only works because 0% of
That only works because 0% of the rooms have neither AC nor cable TV. If we were told that 3% of the rooms have neither AC nor cable TV, then the answer would not be 10%. The answer would be 13%.Also keep in mind that this question is meant to help people practice the Double Matrix method.
I think a Venn diagram is
Venn diagrams work fine for
Venn diagrams work fine for easier questions (like this one), but they're tougher to use with harder questions. This is why I recommend the Double Matrix method for all overlapping sets questions.
I like the double matrix way
Thanks!
I like it too. It's great for
I like it too. It's great for organizing the information.
Hi Brent, The matrix way is
if Total is 100, then CTV =80, K=30
from above equation => 80+30+both = 100
=> 110+both =100
=> both =100-110
=> -10 but apply absolute for our interpretation to make it positive 10.
So Answer is 10
Good idea, Vineet.
Good idea, Vineet.
The only problem with your solution is that it should be: TV + K - BOTH = total
Need to subtract BOTH in order to avoid counting rooms twice.
Here's what I mean:
If room #11A has a TV AND a kitchenette, then we will be counting it once as having a TV, and counting it again as having a kitchenette. To account for this duplication, we subtract BOTH.
Thanks for correcting Brent.
Can we also use the
Great idea!
Great idea!
We can actually use the OR probability here.
That is: P(TV or kitchenette) = P(TV) + P(kitchenette) - P(TV and kitchenette)
IMPORTANT: The question tells us that every room has a TV, a kitchenette, or BOTH. This means there are 0 rooms that have neither a TV nor a kitchenette.
So, P(TV or kitchenette) = 1
Substitute values into the OR probability: 1 = 0.8 + 0.3 - P(TV and kitchenette)
Solve: P(TV and kitchenette) = 0.1 = 10%