There are 32 students in a class. They are taking either biology or chemistry or both. The

number of students taking biology is three times as many as the number of students

taking chemistry. If 4 students are taking both biology and chemistry, how many

students are in biology?

27

Step-by-step explanation:

Let's call the number of students taking chemistry x which makes the biology students 3x. Since the overlap is 4 the amount of students who take chemistry only or biology only is x - 4 and 3x - 4 respectively therefore we can write:

x - 4 + 3x - 4 + 4 = 32

4x - 4 = 32

4x = 36

x = 9

Since x = 9, the amount of biology students is 3x which is 3 * 9 = 27.