Example:
In an elementary school, students know atleast one of the languages, French and Spanish. 125 students know French, 75 students know Spanish and 50 of them know both French and Spanish. How many students are there in the school? Solution:
Venn Diagram:
Let:
n(F) = number of students who know French
n(S) = number of students who know Spanish
Here
n(F) = 125, n(S) = 78, n(F n S) = 50
We have to find n(F u S)
We know that n(F u S) = n(F) + n(S) - n(F n S)
= 125 + 75 - 50
= 150 Directions: Solve the following problems. Also write at least five examples of your own.