Practice Problems on Probability (Easy)

Probability is an important chapter for the students of Class 9, 10, 11, and 12. The Probability Questions, with their answers included in this article, will help you understand the basic concepts and formulas through a number of solved and unsolved questions. These questions cover concepts like Sample Space, Events, Coin Probability, etc. Solving these problems will improve your understanding and problem-solving skills in probability.

Check - Tricks To Solve Probability Questions

Important Formulas on Probability

Solved Practice Problems on Probability (Easy)

Question 1: There are 8 balls in a container, 4 are red, 1 is yellow and 3 are blue. What is the probability of picking a yellow ball?

Probability of picking a ball

Solution:

Probability is equal to the number of yellow balls in the container divided by the total number of balls in the container, i.e. 1/8. 

Question 2: A dice is rolled. What is the probability that an even number has been obtained?

Probability of Rolling a Dice

Solution:

When fair six-sided dice are rolled, there are six possible outcomes: 1, 2, 3, 4, 5, or 6.

Out of these, half are even (2, 4, 6) and half are odd (1, 3, 5). Therefore, the probability of getting an even number is:

P(even) = number of even outcomes / total number of outcomes 

P(even) = 3 / 6

P(even) = 1/2

Question 3: A fair six-sided die is rolled. What is the probability of rolling a number greater than 4?

Solution:

There are 2 favorable outcomes (5 and 6) out of 6 possible outcomes.
Probability = Number of favorable outcomes / Total number of outcomes.
= 2 / 6 = 1 / 3 ≈ 0.3333 or 33.33%.

Question 4: A jar contains 3 red, 4 blue, and 5 green marbles. What is the probability of randomly drawing a red marble?

Solution:

Total marbles = 3 (red) + 4 (blue) + 5 (green) = 12.
Probability of drawing a red marble = Number of red marbles / Total number of marbles.
= 3 / 12 = 1 / 4 = 0.25 or 25%.

Question 5: From a deck of 52 cards, what is the probability of drawing an ace or a king?

Solution:

There are 4 aces and 4 kings in the deck.
Total favorable outcomes = 4 (aces) + 4 (kings) = 8.
Probability = Number of favorable outcomes / Total number of outcomes.
= 8 / 52 = 2 / 13 ≈ 0.1538 or 15.38%.

Question 6: What is the probability of getting an even number when a fair six-sided die is rolled?

Solution:

There are 3 even numbers on a die (2, 4, 6).
Total outcomes = 6.
Probability of rolling an even number = Number of even numbers / Total outcomes.
= 3 / 6 = 1 / 2 = 0.5 or 50%.

Question 7: In a class of 20 students, 12 are girls. What is the probability of randomly selecting a boy?

Solution:

Total students = 20.
Number of boys = Total students - Number of girls = 20 - 12 = 8.
Probability of selecting a boy = Number of boys / Total students.
= 8 / 20 = 2 / 5 = 0.4 or 40%.

Question 8: A spinner with numbers 1 to 5 is spun once. What is the probability of getting an odd number?

Solution:

The number of favorable outcomes are: 1, 3, and 5.
Total outcomes = 5
Probability = Number of favorable outcomes / Total outcomes.
= 3/5 = 0.6 or 60%.

Question 9: What is the probability of not drawing a face card (Jack, Queen, King) from a standard deck of 52 cards?

Solution:

Total face cards in the deck = 12 (4 Jacks, 4 Queens, 4 Kings).
Total non-face cards = 52 - 12 = 40.
Probability of not drawing a face card = Number of non-face cards / Total cards.
= 40 / 52 = 10 / 13 ≈ 0.7692 or 76.92%.

Question 10: A jar contains 10 balls: 3 red and 7 black. What is the probability of drawing a red ball on a single draw?

Solution:

Probability of drawing a red ball and replacing it = 3/10.
Total probability = (3/10) =0.3 or 30%.

Question 11: In a class of 60 students, 30 are boys. If one student is randomly selected, what is the probability of selecting a girl?

Solution:

Total girls = 60 - 30 = 30.
Probability of chosen student being a girl = 30/60.
= 0.5 or 50%

Question 12: A fair six-sided die is rolled. What is the probability of rolling a number greater than 4?

Solution:

Total number of favorable outcome 5,6

Probability = 2/6 ​= 1/3​

=0.333 or 33.33%.

Practice More:

Check - Probability Quiz

Practice Problems on Probability

Question 1: A jar contains 6 balls: 2 are red, 1 is yellow, and 3 are blue. What is the probability of picking a blue ball?

Question 2: A fair six-sided die is rolled. What is the probability of rolling a number less than 3?

Question 3: A jar contains 4 red, 5 green, and 6 blue marbles. What is the probability of randomly drawing a green marble?

Question 4: From a deck of 52 cards, what is the probability of drawing a Queen?

Question 5: A spinner with numbers 1 to 10 is spun once. What is the probability of spinning a number greater than 7?

Question 6: A bag contains 3 red marbles, 4 green marbles, and 3 blue marbles. What is the probability of drawing a green marble?

Question 7: In a class of 25 students, 10 are boys. What is the probability of randomly selecting a boy?

Question 8: A coin is flipped once. What is the probability of getting tails?

Question 9: A deck of 52 cards is shuffled. What is the probability of not drawing an Ace?

Question 10: A fair six-sided die is rolled. What is the probability of rolling an odd number?

Question 11: A jar contains 9 balls: 3 are red, 2 are green, and 4 are yellow. What is the probability of drawing a yellow ball?

Question 12: In a group of 30 students, 18 like cricket and 12 like football. If one student is randomly selected, what is the probability that they like football?

Answer key

1. Probability= 0.5 or 50%.
2. Probability = 0.333 or 33.33%.
3. Probability = 1/3 = 0.333 or 33.33%.
4. Probability = 1/13 ≈ 0.0769 or 7.69%.
5. Probability = 3/10 = 0.3 or 30%.
6. Probability = 4/10 = 0.4 or 40%.
7. Probability = 10/25 = 2.5 = 0.4 or 40%.
8. Probability = 1/2 =0.5 or 50%.
9. Probability = 48/52 = 12/13 ≈ 0.923 or 92.3%.
10. Probability = 3/6 = 1/2 = 0.5 or 50%.
11. Probability = 49 ≈ 0.444 or 44.44%.
12. Probability = 12/30 = 25 = 0.4 or 40%.