Question

In a class 40 students 20 take tea
but not and 18 take coffee then number of students who take neither tea nor coffee​

Answer 1

Answer:

2 is the answer hope it helps

Answer 2

Given are the number of students in a class and students taking coffee or tea, Find the number of students who take neither tea nor coffee.

Explanation:

• Let the whole class represent the universal set denoted by 'U'. Therefore, $n(U)=40$
• Let the number of students who drink Tea belong to a set 'T'.
• Let the number of students who drink Coffee belong to a set 'C'.
• Now the number of students drinking tea but not coffee is given by, $n(T)-n(T\cap C)=20$   ---(a)
• Now the number of students drinking coffee is given by, $n(C)=18$  ---(b)
• Adding (a) and (b) we get, $n(T)+n(C)-n(T\cap C)=38\ \ \ \ \ ->n(T\cup C)=38$  ---(c)
• Now the number of students who drink neither tea nor coffee is given by, $n((T\cup C)')$
• from (c) we get,
• $n((T\cup C)')=n(U)-n(T\cup C)\\->n((T\cup C)')=40-38\\->n((T\cup C)')=2$    
• The number of students who drink neither tea nor coffee is $2$.