What is the probability of getting a head when a coin is tossed?

1/2

A coin has two equally likely outcomes: head and tail. Favourable outcome = 1, total outcomes = 2, so probability = 1/2.

Understanding Probability questions

Probability questions measure how likely an outcome is on a scale from 0 to 1. Counting the sample space correctly matters far more than the final division.

How to approach it

1. List or count every equally likely outcome to get the sample space.
2. Count the outcomes that satisfy the event.
3. Divide favourable outcomes by total outcomes.
4. Check the result lies between 0 and 1, and that complements sum to 1.

Common mistakes to avoid

• Missing outcomes when two dice or two draws are involved.
• Treating dependent events as independent after an item is removed.
• Adding probabilities of events that can happen together.

Where it appears: Appears in CBSE Class 9–12, IGCSE and IB probability units.