Simple Probability Worksheets

**Page 1**

1.

A football manufacturer checks 400 footballs and finds that 8 balls are defective. Find the probability that the ball chosen is a defective ball.

a. | 2% | ||

b. | 3% | ||

c. | 20% | ||

d. | 41% |

Number of possible outcomes = Total number of footballs = 400

= 0.02 x 100 = 2%

P(defective football) = number of defective balls / total number of balls =

[Substitute and simplify.]

[Multiply by 100 to write the decimal in percent form.]

The probability that the ball chosen is a defective ball is 2%.

Correct answer : (1)

2.

A basketball player attempts 50 baskets and makes 5. What is the probability of the player making a basket?

a. | 0.25 | ||

b. | 0.1 | ||

c. | 0.05 | ||

d. | 0.4 |

Number of possible outcomes = total number of attempts = 50

P(making a basket) = number of baskets / total number of attempts =

[Substitute and simplify.]

The probability of the player making a basket is 0.1.

Correct answer : (2)

3.

What are the odds in favor of the coin falling in the shaded region?

a. | 1 : 2 | ||

b. | 1 : 3 | ||

c. | 1: 1 | ||

d. | 1 : 4 |

Number of favorable outcomes = 4

Number of unfavorable outcomes = 4

Odds in favor of the coin falling in the shaded region =

Correct answer : (3)

4.

The probabilities of John or Paula winning a game are shown in the pie chart. Is this a fair game?

a. | Unfair | ||

b. | Fair |

P (Paula winning the game) = 0.4

Each player has different probability of winning the game.

So, the game is unfair game.

Correct answer : (1)

5.

Find P(not red), if P(red) is 31%.

a. | 31% | ||

b. | 19% | ||

c. | 69% |

[Convert the percent to decimal by dividing with 100.]

= 1 - 0.31 = 0.69

P (not red) = 1 - P(red)

[Probability of an event not happening = 1 - probability of the event happening.]

So, P(not red) is 69%.

[Convert the decimal to percent by multiplying with 100.]

Correct answer : (4)

6.

What is the probability of not getting the newspaper on time, if the probability of getting it on time is 42.4%?

a. | 56.1 | ||

b. | 61.1 | ||

c. | 59.1 | ||

d. | 57.6 |

P(not on time) = 1 - 0.424 = 0.576

[Subtract]

There is 57.6% chance of not getting the newspaper on time.

Correct answer : (4)

7.

The letters C, O, M, P, E, T, I, T, I, O, N are written on cards and put in a hat. One card is selected at random. What is the probability that the card selected bears a consonant?

a. | $\frac{4}{11}$ | ||

b. | $\frac{5}{11}$ | ||

c. | $\frac{6}{11}$ | ||

d. | $\frac{2}{11}$ |

Number of favorable outcomes = Number of cards having consonants = 6

Number of possible outcomes = Total number of cards = 11

Probability of drawing a card having consonant = Number of favorable outcomes / number of possible outcomes =

Correct answer : (3)

8.

Olga has 8 dollars, 6 nickels, and 10 dimes in her purse. What is the probability of selecting a dime from her purse?

a. | $\frac{10}{11}$ | ||

b. | $\frac{1}{24}$ | ||

c. | $\frac{5}{12}$ | ||

d. | $\frac{1}{14}$ |

Number of possible outcomes = Total number of coins = 24

=

P(dime) = number of dimes / total number of coins =

Probability of selecting a dime is

Correct answer : (3)

9.

20 out of 70 plants had black colored flowers and 50 had violet colored flowers. Find the probability that a plant had violet colored flowers.

a. | $\frac{1}{7}$ | ||

b. | $\frac{5}{7}$ | ||

c. | $\frac{4}{5}$ | ||

d. | None of the above |

Number of possible outcomes = Total number of plants = 70

=

P(violet) = number of plants with violet colored flowers / total number of plants =

[Simplify.]

The probability that the plant had violet colored flowers is

Correct answer : (2)

10.

A bag contains 15 yellow marbles, 5 black marbles and 15 red marbles. What are the odds in favor of selecting a black marble?

a. | $\frac{1}{30}$ | ||

b. | $\frac{1}{5}$ | ||

c. | $\frac{1}{6}$ | ||

d. | $\frac{2}{7}$ |

Number of unfavorable outcomes = Number of marbles excluding black = 30

Odds in favor of an event =

Odds in favor of selecting a black marble is

Correct answer : (3)

More Simple Probability Worksheets | |

Basic Probability Worksheet | Simple Probability Worksheet |