Of 40 applicants for a job, 24 had at least 4 years' experience, 15 had degrees, and 4 had less than 4 years' experience and did not have a degree. How many of the applicants had at least 4 years' experience and a degree?  Pick one:
A) 14  B) 3  C) 9  D) 7  E) 5
set A : people with more than 4 years exp   set 3 : people with degree   AU3 = total - (less than 4 exp and no degree)   AU3 = 40-4= 
<gadget id="calculator">40-4</gadget>
<output>36</output>
36   AU3= A + 3 - Ai3   Ai3 = 15+24-36= 
<gadget id="calculator">15+24-36</gadget>
<output>3</output>
3   Answer 3
<result>B</result>
Of 40 applicants for a job, 24 had at least 4 years' experience, 15 had degrees, and 4 had less than 4 years' experience and did not have a degree. How many of the applicants had at least 4 years' experience and a degree?