Question 236347
total questions = 100
algebra questions = 60
difficult questions = 20
difficult algebra questions = 8


if algebra questions = 60, then non-algebra questions = 40 because 60 + 40 = 100.


if difficult algebra questions = 8, then difficult non-algebra questions = 12 because 8 + 12 = 20


we have:


total non-algebra questions = 40
difficult non-algebra questions = 12


non-algebra questions that are not difficult are therefore 40-12 = 28.


you have:


28 non-algebra questions that are not difficult
12 non-algebra questions that are difficult
52 algebra questions that are not difficult
8 algebra questions that are difficult.


the total is 28 + 12 + 52 + 8 = 100


total number of questions that are difficult = 8 + 12 = 20


total number of questions that are not difficult = 28 + 52 = 80