Understanding the Calculation of Hospital Emergency Visits A ∩ B and A U B

[robax25]

Homework Statement

A ∩ B and A U B

Relevant Equations

The question is taken from a Book. I don't understand how A ∩ B and AUB is calculated?

A ∩ B and A U B

 

[Mark44]

I don't understand how A ∩ B and AUB is calculated?

The text in the first image describes the events A and B. In words, what does the event A ∩ B mean? What does the event A U B mean?

Per the forum rules, you must show some effort. I've cut you some slack here by not issuing a warning.

 

[robax25]

If I calculate A u B = 5292 + 270 + 246 but there is 242 as well. why is not 242 added? The second question is that A ∩ B = 5292 +953 - 195 but why does he add 953 to the equation?

 

[PeroK]

If I calculate A u B = 5292 + 270 + 246 but there is 242 as well. why is not 242 added? The second question is that A ∩ B = 5292 +953 - 195 but why does he add 953 to the equation?

The $242$ should be added. It looks like a typo.

$953$ is the total number of LWBS, which is set $B$.

 

[FactChecker]

The second question is that A ∩ B = 5292 +953 - 195 but why does he add 953 to the equation?

This is misreading their answer. They are saying that the count of $A \cup B$ is 5292+953-195, not $A \cap B$.

 

[SammyS]

If I calculate A u B = 5292 + 270 + 246 but there is 242 as well. why is not 242 added? The second question is that A ∩ B = 5292 +953 - 195 but why does he add 953 to the equation?

I agree with @PeroK .

5292 + 270 + 246 = 5808 , but Book has the result being 6050 .

Looking further, 6050 − 5808 = 242 .

So, clearly the 242 was omitted mistakenly.