The basic probability formula $P(\text{event}) = \frac{\text{number of favorable outcomes}}{\text{total number of possible outcomes}}$ can only be applied when which condition is met?

There are at least 10 possible outcomes.

All outcomes are equally likely.

The probability is greater than $\frac{1}{2}$.

The number of favorable outcomes is 1.

A box contains 10 balls: 5 are red, 3 are blue, and 2 are green. Which statement is true about drawing one ball at random?

The outcomes 'drawing red' and 'drawing blue' are equally likely.

Drawing a green ball is the most likely outcome.

Each of the 10 individual balls has an equal chance of being drawn.

The outcomes are not equally likely, so probability cannot be calculated.

Understand Likelihood and Probability Practice — Grade 7 math

Lesson 1: Understand Likelihood and Probability — Practice Questions

1. A bag contains 4 red marbles and 6 blue marbles. If one marble is drawn at random, what is the probability it is blue? Express your answer as a fraction. ___
2. A fair six-sided die is rolled once. What is the probability of rolling a number less than 3? Express your answer as a fraction. ___
3. The basic probability formula $P(\text{event}) = \frac{\text{number of favorable outcomes}}{\text{total number of possible outcomes}}$ can only be applied when which condition is met?
- A. There are at least 10 possible outcomes.
- B. All outcomes are equally likely.
- C. The probability is greater than $\frac{1}{2}$.
- D. The number of favorable outcomes is 1.
4. A standard deck has 52 cards. If you draw one card at random, what is the probability of drawing a King? There are 4 Kings in a deck. Express your answer as a fraction. ___
5. A box contains 10 balls: 5 are red, 3 are blue, and 2 are green. Which statement is true about drawing one ball at random?
- A. The outcomes 'drawing red' and 'drawing blue' are equally likely.
- B. Drawing a green ball is the most likely outcome.
- C. Each of the 10 individual balls has an equal chance of being drawn.
- D. The outcomes are not equally likely, so probability cannot be calculated.
6. A bag contains 6 red marbles and 2 green marbles. If you draw one marble at random, what is the probability it is green? The probability is ___.
7. A spinner is divided into 5 equal sections. Four sections are blue and one is orange. What is the probability of the spinner landing on blue? The probability is ___.
8. A special coin is designed to land on heads $80\%$ of the time. If you flip this coin once, what is the probability that it will land on tails? The probability is ___$\%$.
9. A box contains 4 apples and 1 pear. If you pick one piece of fruit without looking, what is the probability of picking an apple? The probability is ___.
10. A basketball player attempts a free throw. The two outcomes are "make" and "miss." Why can't we assume the probability of making the shot is $\frac{1}{2}$?
- A. Because there are only two outcomes.
- B. Because the outcomes are not equally likely.
- C. Because the player might miss on purpose.
- D. Because the probability must be a decimal.