In Exercises 1–6, find the intersection of the sets.

{ 1, 2, 3, ...

Question

In Exercises 1–6, find the intersection of the sets.

{ 1, 2, 3, 4} ⋂ {2, 4, 5}

Accepted Answer

Welcome back. I am so glad you're here. We are asked to find the intersection of the following sets. So the first one starting with a brace, we have 25 28 29 ending that set with a brace and then this is intersecting with. So that's the upside down. You the second set starting with a brace. We have 23 28 closing that set with a brace. Our answer choices are a 27 28 29 in a set answer be the set 23 28. Answer choice C is the set 25 27 29. An answer choice D is the set 28. Alright. We recall from previous lessons that when we have the intersection of two sets, that means what do they share in common? What can we find in both sets? So we're going to create a new set, starting with a brace and then we're going to look for the first number that occurs in both. What's the lowest number on either in either set? The lowest number is 23 is there a 23 and both? Nope, there's only a 23 in the second set. So it's not in both. It gets crossed off. The next number is 25. does occur in both sets. So we can write that in our intersection set. We only write it one time. So 25, what's the next number? The next lowest number is 27, but it only occurs in the set on the left. So, sorry, 27, you're out of here. The next number is 28. does occur in both sets. So we can add that after AO to our set. And now we've run out of numbers in the second set. So anything else left over in the first set isn't going to occur in both. We can say sorry, 29, you're not going to work and we can close our intersection set with a brace. So we've got a set of 25. We look at our answer choices and that matches with answer choice. D. Well done. We'll catch you on the next one.

In Exercises 1–6, find the intersection of the sets. { 1, 2, 3, 4} ⋂ {2, 4, 5}

Concetti chiave

Set Theory

Intersection of Sets

Element Membership

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