#### Solved Examples and Worksheet for Probability of an Event Represented by a Number From 0 to 1

Q1A teacher chooses a student at random from a class of 40 boys. What is the probability that the student chosen is a boy?

A. 1
B. 0
C. 12
D. 140

Step: 1
Number of students in the class is 40. So, the number of possible outcomes is 40.
Step: 2
Since all the students in the class are boys, number of favorable outcomes is 40.
Step: 3
Probability(event) = Number of favorable outcomesNumber of possible outcomes .
[Formula]
Step: 4
P(boy) = 4040 = 1
[Substitute the values.]
Step: 5
The probability that the student chosen is a boy is 1.
Q2A single card is chosen at random from a standard deck of 52 cards. What is the probability that the card chosen is a Jack? A. 352
B. 18
C. 13
D. 113

Step: 1
Total number of possible outcomes is 52.
Step: 2
Number of favorable outcomes is 4.
Step: 3
Probability(event) = Number of favorable outcomesNumber of possible outcomes
[Formula.]
Step: 4
P(a Jack) = 452 = 113
[Substitute the values and simplify.]
Step: 5
The probability that the card chosen is a Jack is 113.
Q3If a marble is chosen at random from a jar containing 13 purple marbles, then what is the probability that the marble chosen is purple?
A. 13
B. 12
C. 1
D. None of the above

Step: 1
Number of purple marbles in the jar is 13. So, the number of possible outcomes is 13.
Step: 2
Since, all the marbles in the jar are purple, the number of favorable outcomes is 13.
Step: 3
Probability(event) = Number of favorable outcomesNumber of possible outcomes
[Formula.]
Step: 4
P(purple) = 1313 = 1
[Substitute the values and simplify.]
Step: 5
The probability that the marble chosen is purple is 1.
Q4What is the probability of selecting a black balloon from a box containing 8 brown balloons and 4 black balloons?

A. 14
B. 112
C. 13
D. 18

Step: 1
Number of favorable outcomes = 4.
[Since there are 4 black balloons.]
Step: 2
Number of possible outcomes = 8 + 4 = 12.
[Add the number of brown balloons and the number of black balloons.]
Step: 3
P(a black balloon) = Number of favorable outcomesNumber of possible outcomes
Step: 4
= 412 = 13
[Substitute and simplify.]
Step: 5
The probability of selecting a black balloon is 13.
Q5Find the probability of drawing a 6 from a stack of cards numbered 0 through 11.
A. 112
B. 14
C. 13
D. 16

Step: 1
Number of possible outcomes is 12.
[Count numbers 0 to 11.]
Step: 2
Number of favorable outcomes is 1.
Step: 3
Probability(event) = Number of favorable outcomesNumber of possible outcomes
[Formula.]
Step: 4
P(6) = 112
[Substitute the values.]
Step: 5
Probability of drawing the card numbered 6 is 112.
Q6What is the probability of choosing an even number from the set of numbers from 1 to 10?
A. 1
B. 110
C. 12
D. 15

Step: 1
There are 10 numbers from 1 to 10. So, the number of possible outcomes is 10.
Step: 2
Number of favorable outcomes is 5.
[The even numbers are 2, 4, 6, 8 and 10.]
Step: 3
Probability(event) = Number of favorable outcomesNumber of possible outcomes
[Formula.]
Step: 4
P(even number) = 510
[Substitute the values.]
Step: 5
= 12
[Simplify.]
Step: 6
Probability of selecting an even number from the set of numbers from 1 to 10 is 12.
Q7What is the probability of selecting a digit, which is multiple of 2, from the numbers 2, 7, 4 and 8?

A. 34
B. 15
C. 25
D. 14

Step: 1
Total number of possible outcomes is 4.
Step: 2
Number of favorable outcomes = 3.
[There are 3 digits which are the multiples of 2.]
Step: 3
Probability(event) = Number of favorable outcomesNumber of possible outcomes
[Formula.]
Step: 4
P(digit which is a multiple of 2) = 34
[Substitute the values.]
Step: 5
Probability of selecting a digit, which is a multiple of 2, from the numbers 2, 7, 4 and 8 is 34.
Q8A ball is chosen at random from 5 violet balls. What is the probability of getting a violet ball?

A. 1
B. 14
C. 12
D. 15

Step: 1
Number of violet balls is 5. So, the number of possible outcomes is 5.
Step: 2
Since all the balls are violet, the number of favorable outcomes is 5.
Step: 3
Probability(event) = Number of favorable outcomesNumber of possible outcomes .
[Formula]
Step: 4
P(violet ball) = 55
[Substitute the values.]
Step: 5
= 1
[Divide]
Step: 6
The probability of getting violet ball is 1.
Q9There are 5 cone ice creams kept in the refrigerator. What is the probability of Emily choosing one out of them?

A. 15
B. 3
C. 14
D. 1

Step: 1
Total number of ice creams is 5. So, the number of possible outcomes is 5.
Step: 2
Number of cone ice creams that Emily chose is 1. So, the number of favorable outcomes is 1.
Step: 3
The probability of Emily choosing one cone ice cream = number of cone ice creams to be chosentotal number of cone ice creams .
Step: 4
= 15
[Substitute the values.]
Step: 5
So, the probability of Emily choosing one cone ice cream is 15.
Q10There are 3 burgundy balls, 7 brown balls, and 5 purple balls in a box. Use a fraction to express the probability of picking a burgundy ball from the box.

A. 215
B. 14
C. 415
D. 15

Step: 1
There are 15 possible outcomes.
Step: 2
There are only 3 burgundy balls.
Step: 3
So, the probability of picking a burgundy ball is 315 = 15.
Q11A card is selected from the deck of 52 cards. Use a fraction to express the probability of selecting a card from the black suit.
A. 15
B. 14
C. 13
D. 12

Step: 1
There are 52 possible outcomes.
Step: 2
There are 26 black cards in a deck of 52 cards.
Step: 3
So, the probability of selecting a card from the black suit is 2652 = 12.
Q12Use a fraction to express the probability of picking a pink book from the shelf. A. 15
B. 5
C. 45
D. 35

Step: 1
There are 5 possible outcomes.
Step: 2
There is 1 pink book.
Step: 3
So, the probability of selecting is pink book is 15.
Q13Use a fraction to express the probability of picking a rectangle from the geometrical figures. A. 1112
B. 712
C. 312
D. 13

Step: 1
There are 12 possible outcomes.
Step: 2
There are 3 rectangles.
Step: 3
So, the probability of picking a rectangle is 312.
Q146 mathematics, 5 science, and 8 French books are arranged on a shelf. Use a fraction to express the probability of picking a mathematics book from the shelf.
A. 619
B. 119
C. 13
D. 719

Step: 1
There are 19 possible outcomes.
Step: 2
There are only 6 mathematics books.
Step: 3
So, the probability of picking a mathematics book is 619.
Q15Use a fraction to express the probability that the letter A is selected from the letters in the word 'SITUATION'.
A. 49
B. 19
C. 79
D. 15

Step: 1
There are 9 possible outcomes.
[There are 9 letters in the word.]
Step: 2
There is 1 'A' letter.
Step: 3
So, the probability of selecting A from the word SITUATION is 19.