The problem states that a bag contains green, red, and blue balls. Anna picks a ball at random and puts it back. We are given a table with the probabilities of picking a green ball (0.55) and a red ball (0.25). The probability of picking a blue ball is represented by $x$. (a) We need to find the value of $x$. (b) We are told there are 20 red balls in the bag and we need to find the number of green balls in the bag. (c) We are asked to complete a probability tree diagram, but the tree diagram is not provided in the image, so it cannot be completed.

Probability and StatisticsProbabilityProbability DistributionsBasic ProbabilityConditional ProbabilityExpected Value
2025/7/14

1. Problem Description

The problem states that a bag contains green, red, and blue balls. Anna picks a ball at random and puts it back. We are given a table with the probabilities of picking a green ball (0.55) and a red ball (0.25). The probability of picking a blue ball is represented by xx.
(a) We need to find the value of xx.
(b) We are told there are 20 red balls in the bag and we need to find the number of green balls in the bag.
(c) We are asked to complete a probability tree diagram, but the tree diagram is not provided in the image, so it cannot be completed.

2. Solution Steps

(a) To find xx, we use the fact that the sum of probabilities of all possible outcomes is

1. $P(green) + P(red) + P(blue) = 1$

0.55+0.25+x=10.55 + 0.25 + x = 1
0.80+x=10.80 + x = 1
x=10.80x = 1 - 0.80
x=0.20x = 0.20
(b) Let NgreenN_{green}, NredN_{red}, and NblueN_{blue} be the number of green, red, and blue balls respectively. Let NtotalN_{total} be the total number of balls. We are given Nred=20N_{red} = 20.
The probability of picking a red ball is P(red)=NredNtotalP(red) = \frac{N_{red}}{N_{total}}. We know P(red)=0.25P(red) = 0.25, so 0.25=20Ntotal0.25 = \frac{20}{N_{total}}.
Ntotal=200.25=80N_{total} = \frac{20}{0.25} = 80
The probability of picking a green ball is P(green)=NgreenNtotalP(green) = \frac{N_{green}}{N_{total}}. We know P(green)=0.55P(green) = 0.55, so 0.55=Ngreen800.55 = \frac{N_{green}}{80}.
Ngreen=0.55×80=44N_{green} = 0.55 \times 80 = 44
(c) Cannot be completed as the tree diagram is not available.

3. Final Answer

(a) x=0.20x = 0.20
(b) The number of green balls is
4

4. (c) Cannot be completed.

Related problems in "Probability and Statistics"

We have a bag with 7 red discs and 5 blue discs. Two discs are drawn at random without replacement. ...

ProbabilityConditional ProbabilityWithout ReplacementCombinatorics
2025/7/15

The problem consists of two parts. (a) A biased square spinner has the following probabilities: Scor...

ProbabilityExpected ValueIndependent EventsConditional ProbabilityDiscrete Probability
2025/7/15

The problem consists of two independent probability questions: (c)(i) A bag contains 15 red beads an...

ProbabilityIndependent EventsConditional ProbabilityWithout Replacement
2025/7/15

We are asked to solve three probability problems: (b) A bag contains 54 red marbles and some blue ma...

ProbabilityConditional ProbabilityCombinatorics
2025/7/15

The problem describes a class of 32 students. We are given information about how many students study...

ProbabilityVenn DiagramsConditional ProbabilitySet Theory
2025/7/15

The problem is based on a Venn diagram representing a group of 50 students. The Venn diagram shows t...

Venn DiagramsSet TheoryProbabilityConditional Probability
2025/7/15

The problem states that the probability of Shalini being late for school on any day is $1/6$. (i) We...

ProbabilityConditional ProbabilityTree Diagrams
2025/7/15

The problem provides a table showing the weekly sales of 1000 traders at a flea market, categorized ...

Frequency DistributionFrequency DensityModal ClassData Analysis
2025/7/8

The problem asks us to perform a pooled t-test to determine if the average monthly sales of Product ...

Hypothesis Testingt-testPooled t-testStatistical SignificanceOne-tailed testSample Statistics
2025/7/8

The problem describes the expected returns of Asset A and Asset B over three years. The task is to d...

CorrelationFinancial MathematicsData Analysis
2025/7/8