Probability

Build fluency with probability notation, expected value, and event reasoning.

Focus points

Use event notation clearly.

Compare independent and dependent events.

Interpret expected value in simple settings.

Session plan

Start with the first two questions to warm up before moving into the harder ones.

Use the calculator only after you have set up the working or estimated the answer.

Work through the page like a focused study sheet instead of jumping around.

How to use this page

A cleaner maths workflow

1. Read the prompt carefully

These pages are meant to feel consistent with the rest of the site, but the maths stays front and center.

2. Solve in order

The question list works best as a progression rather than a random set of cards.

3. Use support tools when needed

You can jump back to the calculator or home without losing the overall flow.

Practice set

6 revision prompts

Question 1

P (A) = 0.4

and

P (B) = 0.3

for independent events, find

P (A \cap B)

Question 2

A fair die is rolled once. Find the probability of getting a number greater than 4.

Question 3

A bag contains 5 red counters and 3 blue counters. One counter is chosen at random. Find the probability it is blue.

Question 4

A game pays $8 with probability 0.2 and loses $2 otherwise. Find the expected value.

Question 5

P (A) = 0.7

, find

P (A^{c})

Question 6

Two coins are tossed. Find the probability of getting exactly one head.