Question

The set O represents the maximum temperatures, in degrees Fahrenheit, recorded in the city of Orlando in a year.

O = {71, 71, 72, 73, 77, 77, 79, 83, 84, 89, 90, 91}

The set T represents the maximum temperatures, in degrees Fahrenheit, recorded in the city of Tampa in a year.

T = {70, 72, 76, 78, 81, 81, 84, 86, 86, 89, 90, 90}

How many elements are in the set O ∪ T?

Answer 1

O U T means the union of O and T. So an element will be in O U T if it's in EITHER of those sets.

Answer 2

3 Right?

Answer 3

Here's a brief example:
A = {1,2,5,9}
B = {1, 3,5, 22}
A U B = {1,2,3,5,9,22}

Answer 4

And A n B is A intersect B, which means just the elements that are in both.
so AnB = {1,5}

Answer 5

So there are three?

Answer 6

No four

Answer 7

I believe you are counting OnT instead of OuT