Simple Probablity

Probability means a chance of something happening.

See the statements below:

It will probably be a cold day today.

Most probably, Daniel will score 80% in his Math test.

There is a chance that my sister visits me today.

In all the statements above, there is a statement of uncertainty because words like “probably”, “most probably”, “chance” indicate that the event may or may not happen.

Example: When a coin is tossed, there are two possibilities – head or tail.

Probability of getting a head = \frac{1}{2}

Probability of getting a tail =\frac{1}{2}

Example: When a die is thrown, it can show a 1, 2, 3, 4, 5 or 6.

Probability of getting a 1, 2, 3, 4, 5 or 6 =\frac{1}{6}

Probability of an event is the number of ways an event can occur divided by the total number of possible outcomes.

Example: What is the probability of spinner landing on pink region?

probability

In all there are 8 parts in the spinner.

So, probability of spinner landing on pink part =\frac{1}{8}

Check Point

  1. There are 4 green, 3 yellow and 2 red marbles in a bag. What is the probability of picking a green marble
  2. Shannon has 5 white erasers and 3 green erasers. What is the probability of picking a white eraser if he picks up any eraser randomly?
  3. When a die is thrown, what is the probability of getting an odd number?
  4. What is the probability of spinner landing on 4?
probablity

 

  1. What is the probability of picking a red card from a deck of 52 cards?
Answer key
  1.   \frac{4}{9}
  2.   \frac{5}{8}
  3.   \frac{1}{2}
  4.   \frac{1}{6}
  5.   \frac{1}{2}

Download/Solve a Worksheet for Simple Probability