Question

In a class, every student knows French or German (or both). 15 students know French, and 17 students know German. What is the largest possible number of students in that class?

Answer 1

Solution:

we are given that

In a class, every student knows French or German (or both).

15 students know French, and 17 students know German.

Suppose there are x student who knows both French and German.

Then Total number of student in the class will be $(15+17-x)=32-x$

But to guess the largest possible number of student in the class we can assume x=0

Hence the largest Possible number of Student in the class=32