In a class of 50 students, 30 take Mathematics, 25 take Biology and 15 take both Mathematics and Biology. How many students take neither Mathematics nor Biology?

In a class of 50 students, 30 take Mathematics, 25 take Biology and 15 take both Mathematics and Biology. How many students take neither Mathematics nor Biology? Correct Answer 10

Given:

The total number of students in a class = 50 

The number of students takes Mathematics = 30

The number of students takes Biology = 25

The number of students take both Mathematics and Biology = 15

Formula used:

n(A ∪ B) = n(A) + n(B) - n(A ∩ B) 

n(A ∪ B)' = n(U) - n(A ∪ B)

where, n(A) = number of elements in A, n(B) = number of elements in B

n(A ∩ B) = number of elements in both A and B, n(A ∪ B) = number of elements in either A or B

n(U) = number of total students

Calculation:

Let the set of total students be U, the set of students takes Mathematics be A

And the set of students takes Biology be C.

According to the question,

n(U) = 50, n(A) = 30, n(B) = 25 and n(A ∩ B) = 15

Now, students take either Mathematics or Biology = n(A ∪ B)

⇒ n(A) + n(B) - n(A ∩ B) 

⇒ 30 + 25 - 15

⇒ 40

So, students take neither Mathematics nor Biology = n(A ∪ B)'

⇒ n(U) - n(A ∪ B)

⇒ 50 - 40

⇒ 10

∴ The students take neither Mathematics nor Biology is 10.

Related Questions

Each question below is followed by two statements I and II. You have to determine whether the data given in the statements are sufficient for answering the question. You should use the data and your knowledge of Mathematics to choose the best possible answer. What is the average weight of new students added? I. In a class 60% students are male and there average weight is 15 kg more than the female students, 9 males and 6 new female students joined the class and the average weight of the class increased by 0.84 II. Total male students in the class is 12 more than female students adding 9 male students to the class increases the average weight of male students by 1 kg and adding 6 female students increases the average weight of female students by 0.6.