From the records at TAB, the following data was collected:

Question

12 students studied Sociology, Economics and Accounting
27 studied Sociology and Accounting
20 studied Sociology and Economics
21 studied Economics and Accounting
36 studied Sociology
36 studied Economics
58 studied Accounting
a) What is the least number of individual student records that were examined?
b) How many students studied Sociology but neither of the Business subjects

I ended up getting that 74 were examined but I don't know how to do b

Answer 1

all 3 = 12
s + e = 20 - 12 = 8
s + a = 27 - 12 = 15
a + e = 21 - 12 = 9
s = 36 - 12 - 8 -15 = 1
e = 36 - 12 - 8 - 9 = 7
a = 58 - 12 - 15 -9 = 22
12 + 8 + 15 + 9 + 1 + 7 + 22 = 74

Answer 2

as usual, for a 3-part Venn diagram,
36+36+58 - (27+20+21) + 12 = 74