<PRE><B>Question 361410</B>
There are 50 students total. &lt;br&gt;

Now we need to find out how many students fit our parameters of Democrat or business major.&lt;br&gt;

There are 31 Democrats, and 13 business majors.  However, 3 of the business majors are ALSO Democrats.&lt;br&gt;

So here are the totals we really have for Democrats and business majors:&lt;br&gt;

{{{31+13-3=41}}}&lt;br&gt;

Thus, the probability of choosing a Democrat or business major is just:&lt;br&gt;

{{{41/50}}} or&lt;br&gt;

0.82&lt;br&gt;

Therefore, P(Democrat or business major)=0.82&lt;br&gt;

We could also use the formula P(A or B) = P(A) + P(B) - P(A and B) to calculate this.  &lt;br&gt;

This is likely how your instructor would like you to solve this problem, see below:&lt;br&gt;

P(D or B)=P(D)+P(B)-P(D and B)&lt;br&gt;

P(D or B)=31/50+13/50-3/50&lt;br&gt;

P(D or B)=41/50=0.82 which agrees with our probability above!&lt;br&gt;

I hope this helps!&lt;br&gt;</PRE>