Question

Suppose two dice (one red, one green) are rolled. Consider the following events. A: the red die shows 1; B: the numbers add to 4; C: at least one of the numbers is 1; and D: the numbers do not add to 10. Express the given event in symbols.

The red die shows 1 and the numbers add to 4.
How many elements does it contain?

Answer 1

A∩B={(1,3)}

It contains two elements.

Explanation:

The event says "The red die shows 1 and the numbers add to 4" then, the clue is in the word "and", as it implies that both events are happening in the same time.

Since 3 is the only number that added to 1 gives 4, then you only have two elements in your event.