Estion 2 of 6 in a town 30 of the households own a dog 20...

estion 2 of 6 > In a town, 30% of the households own a dog, 20% own a cat, and 10% own both a dog and a cat. If we select a household at random, the chance that they own a dog or a cat is: Ο 60% Ο 50% Ο 40%

Transcript

00:01 All right, in this problem we have that in a town, 30 % of households own a dog, 20 % own a cat, and 60 % own neither a dog nor a cat.

00:09 So if we select a household at random, what is the chance that they own both a cat and a dog? so the way i'm going to understand this or help you to understand this is by drawing a venn diagram.

00:19 So we'll have here dogs and we'll have here cats, right? so actually we'll call this c and call this d, just because it's in alphabetical order that way.

00:28 So we know that 60 % lies outside, right? 60 % have neither.

00:33 And then we say, so that means that c and d put together must be 40%.

00:39 Okay, that is the key.

00:41 C and d must be 40%.

00:43 So we'll say c union d, those put together must be 0 .4.

00:49 All right, so what we also know about the union is that it's equal to c plus d minus c intersect d.

00:57 That's the key.

00:58 That's how we're going to find out the intersect d is that area we're looking for.

01:02 That's this area right here.

01:03 C intersect d is what they both have in common.

01:05 Those are the people who have both dogs and cats or both a dog and a cat perhaps.

01:11 Okay, so how do we do that? well, we know that their union is four or 0 .4 and we know that 20 % own a cat.

01:18 So that means that that's equal to 0 .2.

01:20 We have a 30 % own a dog...

Question

estion 2 of 6 > In a town, 30% of the households own a dog, 20% own a cat, and 10% own both a dog and a cat. If we select a household at random, the chance that they own a dog or a cat is: Ο 60% Ο 50% Ο 40%

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