Math question pls help.?

Question

The senior class of Modunk High School has 126 Students. 78 of them are taking Chemistry and 57 are taking PreCalculus.

How many Students are taking Chemestry but not Precalculus?
How many students are taking boths courses?

Answer 1

61 Students are taking Chemistry but not Pre-calculus.
9 students are taking both courses.

57+78=135
135-126=9
78-9=61

Answer 2

78 + 57 = 135, but there are only 126 students, meaning there are 9 people taking both courses. 78 - 9 because, the question asked for those NOT taking precalculus and the 9 are obviously taking it. So, there are 69 students taking chemistry but not precalculus; 9 students taking both; and 48 taking precalculus only.

Answer 3

Not really enough information.

For example 57 could be taking both but we do know that at least 21 chemistry students can't be taking Precalculus since only 57 of the students are. We also know that at least 69 are not taking PreCalculus and 48 are not taking chemistry We do not know what other courses are available but assume that some are as there are more students available. As many as 69 students taking chemistry may not be taking PreCalculus also.

Answer 4

69of them are taking chem but not precalc
9 of them are taking both

if we add 78 and 57 together, we get 135, and the difference between 126 and 135 is 9. so that's how many students are taking both

so out of 78 who are taking chem, 9 of em are taking both. so 78-9=69
69 is how many students taking only chem

Answer 5

only chemistry=69,both subjects=9