Probability worksheet with answers

Free printable Probability worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
xp(x)100.1200.3300.3540?

The table gives the probability distribution of X, but one probability is missing. Find P(X = 40).

x: 10, 20, 30, 40p(x): 0.1, 0.3, 0.35, ?
P(X = 40) =
2.Easy
red: 8blue: 3green: 5

A bag holds 8 red, 3 blue and 5 green balls. You draw one at random. What is the probability P that it is not red?

8 / 3 / 5
P =
3.Medium
xp(x)00.3510.3520.1530.0540.1μ = 1.2

For the distribution shown, find the standard deviation σ of X.

x: 0, 1, 2, 3, 4p(x): 0.35, 0.35, 0.15, 0.05, 0.1
σ =
4.Medium
P(at least one six) = ??1?2?3?4?5?6?7P(six) = 1/6 on each roll

A fair die is rolled 7 times. What is the probability P of getting at least one six?

n = 7
P =
5.Hard
n = 8, p = 0.1: P(X = 5) = ?k012345678

A test has 8 multiple-choice questions. A student who guesses gets each one right with probability 0.1, independently. What is the probability P of exactly 5 correct answers?

n = 8p = 0.1k = 5
P =
6.Hard
n = 8, p = 0.25: P(X = 4) = ?k012345678

A test has 8 multiple-choice questions. A student who guesses gets each one right with probability 0.25, independently. What is the probability P of exactly 4 correct answers?

n = 8p = 0.25k = 4
P =

Answer key

  1. 1. P(X = 40) = 0.25
  2. 2. P = 0.5
  3. 3. σ = 1.249
  4. 4. P = 0.7209
  5. 5. P = 0.0004082
  6. 6. P = 0.08652

Full step-by-step solutions: practise this topic on examproblems.com.