Question

 In a class of 140 Students, 70 students drink tea, 80 students drink coffee and 20 students drink neither tea nor coffee . If a student selected at random drinks tea, what is the probability that he drinks both?*



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Answer 1

Answer:

70/140

Step-by-step explanation:

its because there are only 70 kids who drink tea.....

and I think ur question is wrong

Answer 2

Concept

Probability is actually how many times something is to happen. It is discovered by dividing the range of activities through the range of feasible outcomes.

Given

The total number of students in class is $140$ , the number of students who drinking tea is $70$, the number of students who drinking coffee is $80$ , and the number of students who drink neither tea nor coffee is $20$.

Find

We have to find the probability that how many students are there who drink both coffee and tea.

Solution

The total number of students $n(S)=140$.

Let $A$ be the event that the selected student drinks tea.

The number of students drinking tea is $n(A)=70$.

Let $B$ be the event that the selected student drinks coffee.

The number of students drinking coffee is $n(B)=80$

The number of students who neither drink tea nor drink coffee is $n(A \cup B)'=20$

Let the number of people who drink both is $n(A \cap B)=x$.

Therefore,

$\begin{aligned}n(A)+n(B)-n(A \cap B)+n(A\cup B)&=140\\ 70+80-x+20&=140\\ 170-140&=x\\ 30&=x\end{aligned}$

Now, we will find the probability the student drinks both

$\begin{aligned}P&=\frac{n(A \cap B)}{n(S)}\\ &=\frac{x}{140}\\ &=\frac{30}{140}\\ &=\frac{3}{14}\end{aligned}$

Hence, the probability that the student drinks both is $\frac{3}{14}$.

#SPJ2