Question

Giving a test to a group of students, the grades and gender are summarized below ABCTotalMale1520641Female16121139Total31321780If one student is chosen at random, find the probability that the student was male OR got a/an "C". Round to at least 3 decimal places ____.

Answer 1

The Solution:

Given the table below:

Required:

To find the probability that a student selected at random is a male or got a 'C'.

The required probability is:

$P(a\text{ Male or a C})=P(Male)+P(a\text{ C\rparen}-P(M\cap C)$

In this case,

$\begin{gathered} P(a\text{ Male})=\frac{41}{80} \\ \\ P(a\text{ C})=\frac{17}{80} \\ \\ P(M\cap C)=\frac{6}{80} \end{gathered}$

Substituting, we get

$\begin{gathered} P(a\text{ Male or a C})=\frac{41}{80}+\frac{17}{80}-\frac{6}{80}=\frac{41+17-6}{80}=\frac{52}{80}=0.65 \\ \approx0.650 \end{gathered}$

Therefore, the correct answer is 0.650 (3 decimal place)