Quarter 3 Week 7: Expectations
Quarter 3 Week 7: Expectations
Quarter 3 Week 7: Expectations
Competency
To the Learners
Before starting the module, I want you to prepare your environment for a healthy learning session and make it free from
any possible disturbances to help you focus with the objectives of this module. Read and follow all the instructions below to
achieve the objectives of this kit. Enjoy and have fun!
2. Follow carefully all the instructions indicated in each section of this module.
4. Assess your work using the provided answer key in the module.
Expectations
Lesson 1
Revisiting Probability of Simple and define simple and compound events.
Pre - Test
Direction: Write the letter that corresponds to your answer on your answer sheet.
1. Which of these situations shows a simple event after rolling a fair die?
A. 4 B. 12 C. 24 D. 120
5. If there are two different pasta dishes, three kinds of sandwiches, and four kinds of drinks available in the menu, how
many different Combo Specials can a customer order?
A. 1 B. 9 C. 12 D. 24
7. What is the size of the sample space when three distinct fair coins were tossed simultaneously?
A. 2 B. 4 C. 6 D. 8
8. What is the probability of getting a result of three or an even number when you roll a fair die?
2 1 1 1
A. B. C. D.
3 2 3 6
9. Suppose you roll two fair dice simultaneously. What is the probability of getting a double (two of the same number) or
having a sum of ten?
1 1 1 2
A. B. C. D.
12 18 36 9
10. How many elements are there if you draw a face card or a black jack in a standard deck of 52 cards?
A. 1 B. 2 C. 4 D. 12
if the set shows the union or a sad emoji if the set shows the
The probability is also used in daily living. If you heard, read, or watched about the weather forecast today and for
the next few days, the PAGASA Weather and Flood Forecasting Center may have used the term possibility, prediction, or
probability in the report.
In the next series of lessons, you will learn some basic concepts and probability formulas for different situations that
you may find helpful for predictions and decision making. If you feel excited and ready, then it’s time to explore, read, and
perform all the activities in the next sections of this module. Have fun!
Key Concepts
In calculating probabilities, you will often be asked of the size of the sample space. The size refers to the total number of
outcomes. Hence, on the first example it is two, while on the second example it is six.
The probability of a 𝑷(𝒆𝒗𝒆𝒏𝒕) is equal to the ratio of the number of the favorable (desired) outcomes and the size of
the sample space.
𝐧𝐮𝐦𝐛𝐞𝐫 𝐨𝐟 𝐭𝐡𝐞 𝐟𝐚𝐯𝐨𝐫𝐚𝐛𝐥𝐞 (𝐝𝐞𝐬𝐢𝐫𝐞𝐝) 𝐨𝐮𝐭𝐜𝐨𝐦𝐞𝐬
𝑷(𝒆𝒗𝒆𝒏𝒕) =
𝐬𝐢𝐳𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐬𝐚𝐦𝐩𝐥𝐞 𝐬𝐩𝐚𝐜𝐞
Since a simple event can only have an exactly one outcome, then, the formula can be simplified to
𝟏
𝑷(𝒔𝒊𝒎𝒑𝒍𝒆 𝒆𝒗𝒆𝒏𝒕) =
𝐬𝐢𝐳𝐞 𝐨𝐟 𝐭𝐡𝐞 𝐬𝐚𝐦𝐩𝐥𝐞 𝐬𝐩𝐚𝐜𝐞
Example 1
𝟏
Solution: 𝑃(ℎ𝑒𝑎𝑑𝑠) = Explanation Simple event always has exactly one outcome, while
𝟐
the sample space has a size of two which includes heads and tails.
Example 2 What is the probability of getting a four in a single roll of fair die?
A spinner is divided into four sections with a pointer at the upper tip. Each section is differently labeled
Example 3
using A, B, C, or D. What is the probability that a single spin will be pointing at section C?
Example 4 What is the probability of getting a number greater than five in a single roll of fair die?
𝟏
Solution: 𝑃(𝑓𝑜𝑢𝑟) = Explanation The situation involves a simple event because there is only
𝟔
one number that is greater than five. You can look at the sample space to
verify such claim: one, two, three, four, five, and six. Yay! you’ve guessed it
right! Six is the only number in the sample space which is greater than five.
While it is obvious that the size of the sample space is also six.
You may notice that the formula is basically the same with the formula for probability of simple events before it was
simplified. However, since the number of favorable outcomes vary for different situations involving compound events, then,
you cannot simplify this formula.
Example 1 What is the probability of getting a two or five in a roll of fair die? Express your final answer in lowest terms.
𝟐 𝟏
Solution: 𝑃(𝑒𝑣𝑒𝑛) = 𝑜𝑟 Explanation The compound event includes two simple events which
𝟔 𝟑
could be a two or a five. The phrase “two or five” means that a result of two
is acceptable and the result of five is also acceptable. While the sample
space has a size of six which includes one, two, three, four, five, and six.
Example 2 What is the probability of rolling an even number in a fair die? Express your final answer in lowest terms.
Example 3 What is the probability of drawing a red face card in a single draw from a standard deck of playing cards?
Express your final answer in lowest terms.
Explanation (Refer to the note below if you are not familiar with the
composition of a standard deck of playing cards.) The compound event
𝟔 𝟑 includes six simple events: the Jack, Queen, and King of diamonds suit
Solution: 𝑃(𝑒𝑣𝑒𝑛) = 𝑜𝑟
𝟓𝟐 𝟐𝟔 and the Jack, Queen, and King of hearts suit. While the sample space
includes all the fifty-two cards in the deck with a size of fifty-two (52).
Note: A standard deck of playing cards contains fifty-two (52) cards. The deck is equally divided
into two colors of twenty-six (26) cards each: black and red. Each color is equally divided into two suits
of thirteen (13) cards each: clubs and spades for black while diamonds and hearts for red. Each suit
contains: Ace, 2, 3, 4, 5, 6, 7, 8, 9, 10, Jack, Queen, and King. The Jack, Queen, and King are also
called the face cards.
Activity 1:
Direction: Solve and write your complete solution on your notebook. Then, exchange your answer on the line for
the word on the left of the question to unlock the hidden message.
𝟏 𝟏 𝟏 𝟏 𝟐 𝟏 𝟏 𝟑
𝟔 𝟑 𝟐 𝟓𝟐 𝟏𝟑 𝟖 𝟒 𝟏𝟎
LUCK rolling a number less than two in a single roll of fair die?
MEETING drawing a card of hearts suit from a standard deck of playing cards?
OPPORTUNITY drawing a red ball from a box containing: two blue balls,
PREPARATION spinning yellow from the given wheel Figure 2 Figure 2. Eight Colors Spinning Wheel
Lesson 2
Key Concepts
If an event A has m number of outcomes and if for each of these outcomes another event B has n
number of outcomes, then both events together have mn number of outcomes.
Example Suppose you only have three shirts and two pants left in the closet. How many ways can you dress
for today?
Shirts Pants
3 2
3x2=6
Given any two events A and B, the probability of the union of the events A and B is given by
𝑷(𝑨 ∪ 𝑩) = 𝑷(𝑨) + 𝑷(𝑩) − 𝑷(𝑨 ∩ 𝑩)
which is also referred to as the Addition Rule and sometimes written as
𝑷(𝑨 𝒐𝒓 𝑩) = 𝑷(𝑨) + 𝑷(𝑩) − 𝑷(𝑨 𝒂𝒏𝒅 𝑩)
Example 1 What is the probability of rolling a four or an even number in a single roll of a fair die?
Notice 𝑷(𝒇𝒐𝒖𝒓) + 𝑷(𝒆𝒗𝒆𝒏) double counts the four (4), because four is also an even number.
To fix the error in the previous computation, examine the Venn diagram Figure 4.
In the Venn diagram Figure 4, if you let the event A be the four on a die and let B
be the even numbers on a die, you will notice that event A coincides with event B because
four is a common element for both events A and B. You have learned in the previous
Figure 4. Venn Diagram Showing
module that the collection of all the common elements of any two events such as A and B
the Intersection of Four and Even
Numbers on a Die
is called the intersection which is denoted as 𝑨 ∩ 𝑩. Thus, subtracting 𝑃(𝑨 ∩ 𝑩) from 𝑷(𝑨) + 𝑷(𝑩) eliminates the double
counts and gives the correct result.
𝟒 𝟏
Use the sum obtained for 𝑷(𝑨) + 𝑷(𝑩) in Figure 3 which is equal to and subtract the 𝑷(𝑨 ∩ 𝑩) which is you will
𝟔 𝟔
𝟒 𝟏 𝟒−𝟏 𝟑 𝟏
get
𝟔
−𝟔 = 𝟔
= 𝟔
𝑜𝑟 . To phrase the concepts simply, since you only need to count the numbers two,
𝟐
four (not double counting four), and six, then you only have three (3) favorable outcomes divided by the size of your sample
𝟏
space which is six (6). Therefore, is the correct solution.
𝟐
Example 2
What is the probability of drawing a red face card or a diamond from a standard deck of playing cards?
𝑷(𝒓𝒆𝒅 𝒇𝒂𝒄𝒆) + 𝑷(𝒅𝒊𝒂𝒎𝒐𝒏𝒅) − 𝑷(𝒓𝒆𝒅 𝒇𝒂𝒄𝒆 ∩ 𝒅𝒊𝒂𝒎𝒐𝒏𝒅) Note You may apply the
FCP to find the number of
𝟔 𝟏𝟑 𝟑 red face cards.
+ −
Solution 𝟓𝟐 𝟓𝟐 𝟓𝟐 Red Suits × Face Cards
𝟔 + 𝟏𝟑 − 𝟑 𝟏𝟔 𝟒 𝟐 × 𝟑
= 𝒐𝒓
𝟓𝟐 𝟓𝟐 𝟏𝟑
= 𝟔 𝑅𝑒𝑑 𝑓𝑎𝑐𝑒 𝑐𝑎𝑟𝑑𝑠
However, DO NOT apply FCP for finding the intersection because of its restrictive nature UNLESS you
know exactly what you are doing.
The intersection only has the three red face cards of diamonds: Jack, Queen, and King of diamonds.
There are three B’s: blue There are three blue colors:
Solution
B, orange B, and pink B. two blue A’s and a blue B.
Not all situations that involve probability of union of two (or more) events have common elements. Explore and
study the next example.
Example 4 What is the probability of getting at least two heads when you flip a one-peso, a five-peso, and a ten-
peso coin simultaneously?
Figure 6. Sample Space of Flipping Three Distinct Coins How to count the size of the sample space?
If you do not wish to make a tree diagram or list of the sample space to know its size, then you may apply the
Fundamental Counting Principle.
One Peso Five Peso Ten Peso Result Each coin has two possible outcomes. By multiplying all
2 × 2 × 2 = 8 the numbers corresponding to the total number of
possible outcomes for each coin (𝟐 × 𝟐 × 𝟐) you can get the size of the sample space (8) when all the coins are flipped
simultaneously.
The 𝑷(𝒂𝒕 𝒍𝒆𝒂𝒔𝒕 𝒕𝒘𝒐 𝒉𝒆𝒂𝒅𝒔) means that a result with exactly two heads are allowed as well as the
Solution result with three heads. Hence, you could also write the problem as
There are three results that There is only one result Notice that there is no common element
show exactly two heads: that shows three heads between the two events (HHT, HTH,
HHT, HTH, and THH. which is HHH. (Refer to THH, and HHH), therefore their
(Refer to Figure 6.) Figure 6.) intersection has a size of zero.
you will learn more about this kind of probability in your next module. Have fun learning!
Activity 2:
Direction: Solve and write your complete solution on your notebook. Match the picture with an answer provided in the box
below. Then, guess the word that can produce by each pair of pictures.
𝟓 𝟏 𝟒 𝟏 𝟕
𝟏
𝟖 𝟒 𝟏𝟑 𝟐 𝟖
What is the probability of drawing an ace or a spade from a standard deck of playing cards?
What is the probability of drawing a red or a black card from a standard deck of playing cards?
What is the probability of getting a three of a kind (three of the same side of the coin) when you
flip a one-peso, a five-peso, and a ten-peso coins simultaneously?
What is the probability of getting a result with at most two tails when you flip a one-peso, a
five-peso, and a ten-peso coins simultaneously?
Using the spinner in Figure 5, what is the probability of spinning an A or a pink in a single spin?
Using the spinner in Figure 5, what is the probability of spinning a C or a blue in a single spin?
Remember
If an event A has m number of outcomes and if for each of these outcomes another event B has n number of outcomes,
then both events together have mn number of outcomes.
Addition Rule
The probability of union of events A and B is given by 𝑷(𝑨 ∪ 𝑩) = 𝑷(𝑨) + 𝑷(𝑩) − 𝑷(𝑨 ∩ 𝑩)
Remember that if the situation involves the probability of the union of two events for which the events have no
common elements the formula can be simplified to 𝑷(𝑨 ∪ 𝑩) = 𝑷(𝑨) + 𝑷(𝑩)
I. Direction: Answer each problem involving probability of simple and compound events. Write your complete
solutions on your notebook and encircle/box your final answers. Express your final answers in lowest terms.
Use the Eight Colors Spinning Wheel Figure 2. What is the probability of spinning
A deck of twenty-six alphabet cards contains one card for each letter. What is the probability of drawing
8. What is the probability of rolling an even or odd in a single roll of a fair die?
9. What is the probability of drawing a number card from a standard deck of playing cards?
10. What is the probability of drawing a red spade from a standard deck of playing cards?
II. Direction: Answer each problem involving probability of union of two events. Write your complete solutions on
your notebook and encircle/box your final answers. Express your final answers in lowest terms.
4. What is the probability of rolling a sum of six or a sum of seven when you roll two
5. What is the probability of rolling a sum of eight or a two of a kind when you roll two different dice at once?
6. What is the probability of drawing a face card or a black card in a single draw from a standard deck of playing cards?
7. What is the probability of drawing a red face card or a club in a single draw from a standard deck of playing cards?
8. What is the probability of getting a result with at most one heads or with exactly two tails when you flip three distinct
coins simultaneously?
9. Suppose you simultaneously flipped a coin and rolled a die, what is probability of obtaining a combined result of a
heads and two or a heads and even.
10. Suppose you simultaneously flipped a coin and rolled a die, what is probability of obtaining a combined result of a
heads and three or a tails and odd.
Post-test
Direction: Write the letter that corresponds to your answer on your answer sheet.
1. Which of these situations shows a simple event after rolling a fair die?
4. How many distinct ways can you keep four different books in a book shelf?
A. 4 B. 12 C. 24 D. 120
5. Assume that you own a “merienda” food stall and you want to offer Busog Combo Specials consisting of a pasta dish,
a sandwich, and a drink. How many unique orders of Busog Combo Specials can you offer if you have these options on the
A. 1 B. 9 C. 12 D. 24
7. What is the size of the sample space when three distinct fair coins were tossed simultaneously?
A. 2 B. 4 C. 6 D. 8
8. What is the probability of getting a result of three or an even number when you roll a fair die?
2 1 1 1
A. B. C. D.
3 2 3 6
9. Suppose you roll two fair dice simultaneously. What is the probability of getting a double (two of the same number) or
having a sum of ten?
1 1 1 2
A. B. C. D.
12 18 36 9
10. How many elements are there if you draw a face card or a black jack in a standard deck of 52 cards?
A. 1 B. 2 C. 4 D. 12
Reflection:
Write a journal about your understanding of the lesson on your notebook. Write on your journal about the importance
and how you will be able to use your knowledge of the lesson in real life situations.