Among 500 freshmen pursuing a business degree at a university, 317 are enrolled in an economics course, 225 are enrolled in a mathematics course, and 146 are enrolled in both an economics and a mathematics course. What is the probability that a freshman selected at random from this group is enrolled in each of the following? (Enter your answers to three decimal places.)

Question

anonymous · Answer

(a) an economics and/or a mathematics course
 

(b) exactly one of these two courses
 

(c) neither an economics course nor a mathematics course

anonymous · Answer

What are you events?  Create variables for your events first.

anonymous · Answer

"an economics and/or a mathematics course"
This is the union of two events.

anonymous · Answer

Is there a specific formula I need to use for this problem type?

anonymous · Answer

First come up with events and try to identify what probabilities you actually are trying to find.  Then we can talk formula.

anonymous · Answer

The formula are the easy part, the hard part is identifying events and analysis.

anonymous · Answer

So events would be economics course, math course, and both econ and math?

anonymous · Answer

Don't create events for things that can be expressed in terms of events you already have.

anonymous · Answer

The third event you mentioned is just the intersection of the first two.

anonymous · Answer

Now assign a variable to the events.  I prefer $A$ and $B$.

anonymous · Answer

so A would be math and B would be econ or vice versa?

anonymous · Answer

That is fine.  They are variables it doesn't matter.

anonymous · Answer

how do you express "an economics and/or a mathematics course"  in terms of $A$ and $B$?

anonymous · Answer

Intersection is and and union is or right? I can't find the symbol for intersection on here.

anonymous · Answer

In this case,  and/or   really just means or.

anonymous · Answer

|dw:1392189251894:dw|?