Answer:
A∩B={(1,3)}
It contains two elements.
Step-by-step 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.