the table below gives the probability density of grades for a particular class.\ngrade a b c d…

the table below gives the probability density of grades for a particular class.\ngrade a b c d f\nprobability 0.22 0.29 0.27 0.15 0.07\nif a student is selected at random, what is the probability that their grade is a b or c?\np = ?

the table below gives the probability density of grades for a particular class.\ngrade a b c d f\nprobability 0.22 0.29 0.27 0.15 0.07\nif a student is selected at random, what is the probability that their grade is a b or c?\np = ?

Answer

Explanation:

Step1: Identify relevant probabilities

The probability of getting a B is $P(B)=0.29$ and the probability of getting a C is $P(C)=0.27$.

Step2: Use addition rule for mutually - exclusive events

Since a student can't get a B and a C at the same time (mutually - exclusive events), the probability of getting a B or C is $P(B\cup C)=P(B)+P(C)$. $P(B\cup C)=0.29 + 0.27$

Answer:

$0.56$