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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1.Easy
xp(x)100.35200.3530?400.15

The table gives the probability distribution of X, but one probability is missing. Find P(X = 30).

x: 10, 20, 30, 40p(x): 0.35, 0.35, ?, 0.15
P(X = 30) =
2.Easy
xp(x)10.220.13?40.0550.3

The table gives the probability distribution of X, but one probability is missing. Find P(X = 3).

x: 1, 2, 3, 4, 5p(x): 0.2, 0.1, ?, 0.05, 0.3
P(X = 3) =
3.Medium
P(at least one six) = ??1?2?3?4?5P(six) = 1/6 on each roll

A fair die is rolled 5 times. What is the probability P of getting at least one six?

n = 5
P =
4.Medium
red: 5blue: 9

A bag holds 5 red and 9 blue balls. You draw two balls without putting the first one back. What is the probability P that both are red?

5 / 9
P =
5.Hard
xp(x)00.2510.120.3530.3μ

X has the distribution shown, and Y = 2X − 3. Find the standard deviation σY of Y.

x: 0, 1, 2, 3p(x): 0.25, 0.1, 0.35, 0.3Y = 2X − 3
σY =
6.Hard
n = 5, p = 0.6: P(X = 3) = ?k012345

A test has 5 multiple-choice questions. A student who guesses gets each one right with probability 0.6, independently. What is the probability P of exactly 3 correct answers?

n = 5p = 0.6k = 3
P =

Answer key

  1. 1. P(X = 30) = 0.15
  2. 2. P(X = 3) = 0.35
  3. 3. P = 0.5981
  4. 4. P = 0.1099
  5. 5. σY = 2.289
  6. 6. P = 0.3456

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