1

Problem

In a box of marbles, there are 15 red marbles, 10 green marbles, 20 blue marbles, and 5 yellow marbles. If one marble is chosen at random, what is the probability of selecting a marble that is either red or green?

2

Step

The box contains: 15 red marbles, 10 green marbles, 20 blue marbles, 5 yellow marbles.

3

Step

Calculate the total number of marbles

The total number of marbles is 15 + 10 + 20 + 5 = 50 marbles

4

Step

The favorable outcomes are the marbles that are either red or green:

Red marbles = 15

Green marbles = 10

5

Step

Calculate the number of favorable outcomes:

The total number of red or green marbles is = 15 + 10 = 25 marbles

6

Step

The probability of selecting a red or green marble

\$P("red or green") = "(Total number of marbles)" / "(Number of red or green marbles)"\$

\$(25) / (50)\$

\$1 / 2\$

7

Solution

Therefore, the probability of selecting a marble that is either red or green is \$1/2\$.

8

Sumup

Please summarize steps

Choices

9

Choice-A

This option is incorrect because \$1/3\$ does not accurately represent the probability of selecting red or green

Wrong \$1/3\$

10

Choice-B

This option is incorrect because \$1/5\$ is not equal to \$(25)/(50)\$ which represents the actual probability

Wrong \$1/5\$

11

Choice-C

This option is incorrect because it implies that the number of red and green marbles is one-eleventh of the total marbles. However \$1/2\$ not equal to \$1/(11)\$

Wrong \$1/(11)\$

12

Choice-D

This option is correct because \$1/2\$ is the probability of selecting a marble that is either red or green

Correct \$1/2\$

13

Answer

Option

D

14

Sumup

Please summarize choices