Question

In a mathematics and Science test conducted, 28 passed in Mathe- matics 5 passed in only Science and 7 failed in both subjects. how many students wrote the test ?​

Answer 1

40 students

Explanation:

In order to find the total number of test-takers, we must add the students together with no overlap.

We must realize there are 4 types of students:

Students who only passed in Math (x)

Students who only passed in Science (5)

Students who passed in both Math and Science (y)

Students who passed in neither Math nor Science (7)

Although we don't know how many people passed in only math or math and science, all of those students passed in math. The 28 students that passed in math include both of these categories and only these 2 categories. This said, we know that the number of x+y=28.

Now, all we have to do is add the numbers together.

5+7+28=40

Hence, we know that 40 students wrote the test.