🚀 Middle School
| IB • Mathematics

Probability

Theoretical and experimental probability.

1 Lesson 1 MCQ 1 Mnemonic
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Lesson

Probability — Lesson

1) Hook — The IPL Super Over Probability!

Imagine you are watching the IPL final, and the match is tied. The game goes into a Super Over, where each team gets one over (6 balls) to score runs. Now, you wonder: What is the chance that a bowler will bowl a dot ball (no run) on the very next ball? Probability helps us answer such questions and predict the chances of events happening in cricket, Bollywood award wins, or even daily life!

2) Core Concepts — What is Probability?

Probability is the measure of how likely an event is to occur. It is a number between 0 and 1, where:

  • 0 means the event will never happen.
  • 1 means the event will always happen.

We calculate probability using the formula:

Probability of an event = (Number of favorable outcomes) / (Total number of possible outcomes)

Example 1: Tossing a Coin

When you toss a fair coin, there are 2 possible outcomes: Heads or Tails.

Event Favorable Outcomes Total Outcomes Probability
Getting Heads 1 (Heads) 2 (Heads, Tails) 1/2 = 0.5

Example 2: Rolling a Die

A standard die has 6 faces numbered 1 to 6. What is the probability of rolling a 4?

Event Favorable Outcomes Total Outcomes Probability
Rolling a 4 1 (face with 4) 6 (faces 1 to 6) 1/6 ≈ 0.167

3) Key Formulas/Rules

Basic Probability Formula:

P(Event) = Number of favorable outcomes / Total number of possible outcomes

Complement Rule:

The probability that an event does not happen is:

P(Not Event) = 1 – P(Event)

Sum of all probabilities:

The sum of probabilities of all possible outcomes of an experiment is always 1.

4) Did You Know?

In Bollywood, the chance of winning the Filmfare Best Actor Award is like a probability game! With many talented actors like Shah Rukh Khan, Ranveer Singh, and Amitabh Bachchan competing, the probability of any one actor winning depends on many factors, but mathematically, if there are 5 nominees, the chance of winning (assuming equal chances) is 1/5 = 0.2 (20%). However, just like in probability, real life has surprises and uncertainties!

5) Exam Tips

  • Read the question carefully: Identify the total number of outcomes and favorable outcomes clearly.
  • Write the formula first: Always start by writing P = favorable / total to avoid confusion.
  • Check if the event is certain or impossible: Remember, probability 0 means impossible, 1 means certain.
  • Watch out for “at least” questions: For example, “at least one head” means 1 minus the probability of no heads.
  • Practice word problems: Board exams often include real-life scenarios, so practice problems related to games, cards, dice, and daily life.
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MCQ Practice

Probability — Mcq

3
Memory Trick

Probability — Mnemonic

Mnemonic 1: PROBABILITY 🏏

“Possibility Runs On Balls, All Batsmen In Line In The Yard!”

Explanation: Just like in cricket, the probability of scoring runs depends on the balls played and the batsmen’s chances. Probability tells us how likely an event is to happen — like a batsman hitting a six!

Mnemonic 2: “SAMBHAL KE PROBABILITY” 🎲

Success Amounts Mean Better Happenings, Always Learn Knowing Event’s PROBABILITY.

Hindi phrase meaning: “सावधान रहो, संभावना समझो।” (Be careful, understand the probability.)

Explanation: This reminds students to carefully analyze the chances before making decisions — just like choosing the right shot in cricket or the right move in a game.

Mnemonic 3: Probability Formula Fun 🎉

P = Favourable Events / Total Events

“FET” = Favourite Events Total

Funny rhyme: “If you want to win the bet, count your FET!” (Like counting your runs before hitting a boundary!)

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