Question

In a class, there are x girls and y boys, a student is selected at random, then the probability of selecting a boy is :

• A. $\frac{x}{y}$
• B. $\frac{x}{(x+y)}$
• C. $\frac{y}{(x+y)}$
• D. $\frac{y}{x}$

Answer 1

Answer: (C)

$\frac{y}{(x+y)}$

In a class, there are $x$ girls and $y$ boys, a student is selected at random

The sample space contains all students

So, total no. of students $=x+y$

The number of boys are $y$

Therefore the probability of selecting a boy is $P\left(E\right)=\frac{y}{x+y}$