kwizNET Subscribers, please login to turn off the Ads!
Email us to get an instant 20% discount on highly effective K-12 Math & English kwizNET Programs!

Online Quiz (Worksheet A B C D)

Questions Per Quiz = 2 4 6 8 10

High School Mathematics - 2
13.5 Combination of Two Events

Combination of two Events

  1. Union of Events
    If A and B are 2 events of sample space S then A U B ( or A+B ) is the event that either A or B or both take place.
  2. Intersection of Events
    If A and B are 2 events of sample space S then A B (or AB ) is the event that both A and B take place.
  3. Mutually Exclusive Events
    Two events A and B are said to be mutually exclusive if they cannot occur simultaneously. In such case ( A B) is a { } set.
  4. Exhaustive Events
    Two events are said to be Exhaustive if A U B = S (sample space)

Addition Theorem

P( A U B) = P(A) + P(B) - P( A B)

Solved Example

A box contains 36 tickets numbered 1 to 36. One ticket is drawn at random. Find the probability that the number on the ticket is either divisible by 3 or is a perfect square.

n(S)= 36
Let A be the event that the number is divisible by 3.
A = { 3,6,9,12,15,18,21,24,27,30,33,36 }
n(A) = 12 P(A) = 12/36
Let B be the event that the number on the ticket is a perfect square.
P(B) = { 1,4,9,16,25,36 }
n(B) = 6
P(B) = 6/36
Now A B = { 9, 36}
n( A B )= 2
P( A B ) = 2/36
The required probability is P(A U B)
P(A U B) = P(A) + P(B) - P( A B)
= 12/36 + 6/36 -2/36
= 4/9

Q 1: In a coffee shop the probaility that a customer drinks Capuccino is 0.5 and that he drinks mocaccino is 0.4 and that he drinks something from each of them is 0.25. Find the probability that the customer drinks at least one of the two.

Question 2: This question is available to subscribers only!

Subscription to kwizNET Learning System offers the following benefits:

  • Unrestricted access to grade appropriate lessons, quizzes, & printable worksheets
  • Instant scoring of online quizzes
  • Progress tracking and award certificates to keep your student motivated
  • Unlimited practice with auto-generated 'WIZ MATH' quizzes
  • Child-friendly website with no advertisements
  • Choice of Math, English, Science, & Social Studies Curriculums
  • Excellent value for K-12 and ACT, SAT, & TOEFL Test Preparation
  • Get discount offers by sending an email to

Quiz Timer