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Lesson Example Discussion Quiz: Class Homework

Step-4

Title: Probability

Grade: 1400-a Lesson: S4-L3

Explanation: Hello Students, time to practice and review the steps for the problem.

Lesson Steps

Step	Type	Explanation	Answer
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	Step	Therefore, the probability of selecting a marble that is either red or green is \$1/2\$.
8	Choice.A	This option is incorrect because \$1/3\$ does not accurately represent the probability of selecting red or green	\$1/3\$
9	Choice.B	This option is incorrect because \$1/5\$ is not equal to \$25/50\$ which represents the actual probability	\$1/5\$
10	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\$	\$1/11\$
11	Choice.D	This option is correct because \$1/2\$ is the probability of selecting a marble that is either red or green	\$1/2\$
12	Answer	Option	D
13	Sumup	Can you summarize what you’ve understood in the above steps?

Step

Type

Explanation

Answer

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?

Step

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

Step

Calculate the total number of marbles:
The total number of marbles is: 15 + 10 + 20 + 5 = 50 marbles.

Step

The favorable outcomes are the marbles that are either red or green:
Red marbles = 15
Green marbles = 10

Step

Calculate the number of favorable outcomes:
The total number of red or green marbles is = 15 + 10 = 25 marbles.

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\$

Step

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

Choice.A

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

\$1/3\$

Choice.B

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

\$1/5\$

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\$

\$1/11\$

Choice.D

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

\$1/2\$

Answer

Option

Sumup

Can you summarize what you’ve understood in the above steps?