Begin with n(B∩C∩S)=g=21 Then go to n(B∩S)=f+g=33, and you can get f. Then go to n(B∩C)=d+g=31, and you can get d. Then go to n(B)=a+d+f+g=47, and you can get a. Then go to n[(B∩C)∪(B∩S)∪(C∩S)]=d+g+f+h=51, and you can get h. Then go to n(C)=d+e+g+h=46, and you can get e. Then go to n(S)=f+g+h+i=52, and you can get i. Finally, go to "75 patients", a+d+e+f+g+h+i+j=75, and you can get j. (a) had high blood pressure or high cholesterol, but not both? That's a+f+e+h. (b) had fewer than two of the conditions listed? That's a+e+i+j. (c) were smokers, but did not have high blood pressure or high cholesterol? That's i. (d) did not present exactly two of the conditions on the list? That's a+e+i+g+j You can fill in the question marks in the Venn diagram, then add them up to answer the questions. Edwin