Buzz
Exercises 1, 2, 3, 4 from the lesson Introduction to Random Events will be elaborately explained in the solution manual for Grade 7 Math on page 89 of Chân Trời Sáng Tạo Book. Students can refer to it to easily complete homework and strengthen their knowledge after studying this lesson.
Refer to several excellent Math 7 materials:
- Grade 7 Math solution book Chân Trời Sáng Tạo
- Grade 7 Math on pages 32, 33 of Textbook 2, Cánh Diều Book - Exercise 6. Probability of random events in some simple games
- Grade 7 Math on page 50 of Textbook 2, Kết Nối Tri Thức Book - Exercise 29: Introduction to events
Solving Grade 7 Math on page 89 of Textbook 2, Chân Trời Sáng Tạo Book
Introduction to Random Events
Solving Exercise 1 Page 89 Mathematics Grade 7 Textbook
Statement: Tossing a coin twice. Determine the occurring events among the following. Given both tosses result in tails.
A: 'Tails appears on the second toss';
B: 'Getting identical outcomes in both tosses';
C: 'At least once during the toss, the head side appears'.
Explanation:
Based on the condition: both tosses result in tails to determine the occurred event.
Answer:
Since both tosses resulted in tails, events: 'Tails appears on the second toss' and 'Getting identical outcomes in both tosses' have occurred.
2. Solve Exercise 2 Page 89 Mathematics Grade 7 Textbook
Statement: Minh spins the arrow on the spinner in the figure and observes which section it points to when it stops.
Among the following events, identify the event that is certain, impossible, random.
A: 'The pointer points to a cell with a number not less than 1';
B: 'The pointer points to a cell with white color';
C: 'The pointer points to a cell with purple color';
D: 'The pointer points to a cell with a number greater than 6'.
Guidelines:
A certain event is an event that always occurs.
An impossible event is an event that never occurs.
A random event is an event that cannot be known in advance whether it will occur or not.
Answer:
+ Since all the numbers on the spinner are greater than or equal to 1, event A is a certain event.
+ When spinning the spinner, the pointer can land on a cell with white, green, or red color. Therefore, event B is a random event.
+ Since the spinner does not have a purple cell, event C is an impossible event.
+ The numbers on the spinner do not exceed 6. Therefore, event D is an impossible event.
3. Solve Exercise 3 Page 89 Mathematics Grade 7 Textbook
Statement: A box contains 3 ink pens and 1 pencil. Two pens are randomly picked from the box at the same time. Among the following events, identify the event that is certain, impossible, random.
A: 'Drawing 2 ink pens';
B: 'Drawing 2 pencils';
C: 'Having at least 1 ink pen among the two pens picked';
D: 'Having at least 1 pencil among the two pens picked'.
Guidelines:
A certain event is an event that always occurs.
An impossible event is an event that never occurs.
A random event is an event that cannot be known in advance whether it will occur or not.
Answer:
+ Since there are 3 ink pens and 1 pencil, when randomly picking 2 pens from the box, the 2 pens picked can be 2 ink pens or 1 pencil and 1 ink pen. Therefore, events A and D are random events.
+ With only 1 pencil available, it is impossible to pick 2 pencils, and there must be at least 1 ink pen among the two pens picked. Therefore, event B is an impossible event, and event C is a certain event.
4. Solve Exercise 4 Page 89 Mathematics Grade 7 Textbook
Statement: A box contains 1 blue ball, 1 red ball, and 1 yellow ball. A ball is randomly picked, its color observed, returned to the box, and then another ball is randomly picked. Among the following events, identify the event that is certain, impossible, random.
A: 'The ball picked the second time is red';
B: 'The ball picked the second time is the same color as the first ball';
C: 'The ball picked the first time is pink';
D: 'At least once, a green ball is picked'.
Instructions:
A certain event is an event that always occurs.
An impossible event is an event that never occurs.
A random event is an event that cannot be known in advance whether it will occur or not.
Answer:
Since randomly picking 1 ball, observing its color, returning it to the box, and then picking another ball, the second ball picked could have the same color as the first ball. The second ball could be red, green, or yellow. Therefore, events A, B, D are random events.
Since there are no pink balls among the 3 balls, event D is an impossible event.
Here is the guidance for solving math exercises for grade 7 page 89, volume 2. Students should refer to the solution for grade 7 math exercises on pages 93, 94, volume 2, and review the solution for grade 7 math exercises on page 84, volume 2 to consolidate knowledge.
- Grade 7 Math Solution page 93, 94, volume 2 of Creative Horizon - Exercise 2: Getting acquainted with the probability of random events
- Grade 7 Math Solution page 84, volume 2 of Creative Horizon - Last exercise of chapter 8
