Question

[20 POINTS] At a certain high school, 15 students play stringed instruments, 20 students play brass instruments, and 5 students play neither stringed nor brass instruments. what is the probability that a randomly selected student plays either a string or brass instrument?

Answer 1

Answer:

$P(A\cup B)= 0.875$

Step-by-step explanation:

From the diagram, none of the students play both instruments.

This means the two events are mutually exclusive.

$P(A\cup B)=P(A)+P(B)$

The number of people playing instruments is 20.

$P(A\cup B)= \frac{20}{40} + \frac{15}{40}$

$P(A\cup B)= \frac{35}{40}$

$P(A\cup B)= 0.875$

Answer 2

Answer:

0.88

Step-by-step explanation:

15/40+20/40=7/8

Converted into a decimal 0.875

then rounded to the nearest hundredth= 0.88