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.

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Name: ____________________   Date: ____________

1.Easy
red: 7blue: 5green: 5

A bag holds 7 red, 5 blue and 5 green balls. You draw one at random. What is the probability P that it is blue?

7 / 5 / 5
P =
2.Easy
xp(x)0?10.3520.35

The table gives the probability distribution of X, but one probability is missing. Find P(X = 0).

x: 0, 1, 2p(x): ?, 0.35, 0.35
P(X = 0) =
3.Medium
xp(x)00.310.3520.35μ = 1.05

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

x: 0, 1, 2p(x): 0.3, 0.35, 0.35
σ =
4.Medium
n = 14k = 3N = ?

In how many ways N can a committee of 3 people be chosen from a group of 14? The order does not matter.

n = 14k = 3
N =
5.Hard
n = 7, p = 0.6: P(X = 1) = ?k01234567

A test has 7 multiple-choice questions. A student who guesses gets each one right with probability 0.6, independently. What is the probability P of exactly 1 correct answers?

n = 7p = 0.6k = 1
P =
6.Hard
n = 6, p = 0.7: P(X = 5) = ?k0123456

A test has 6 multiple-choice questions. A student who guesses gets each one right with probability 0.7, independently. What is the probability P of exactly 5 correct answers?

n = 6p = 0.7k = 5
P =

Answer key

  1. 1. P = 0.2941
  2. 2. P(X = 0) = 0.3
  3. 3. σ = 0.8047
  4. 4. N = 364
  5. 5. P = 0.0172
  6. 6. P = 0.3025

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