# Coin Toss Probability Formula: 2 Coin, 3 Coin and 4 Coin Toss with Solved Examples

#### ByMayank

Oct 28, 2023

Coin tossing is a classic probability experiment that can help us understand the fundamental concepts of probability theory. In this comprehensive guide, we will explore the probability of outcomes in 2-coin, 3-coin, and 4-coin toss scenarios. We will provide the formulas for calculating these probabilities and offer solved examples to illustrate how to apply them.

2-Coin Toss Probability

In a 2-coin toss scenario, there are four possible outcomes: HH (two heads), HT (head-tail), TH (tail-head), and TT (two tails). The probability of each outcome can be calculated as follows:

1. Probability of getting two heads (HH):
• P(HH) = (1/2) * (1/2) = 1/4
2. Probability of getting one head and one tail (HT or TH):
• P(HT) = (1/2) * (1/2) = 1/4
• P(TH) = (1/2) * (1/2) = 1/4
3. Probability of getting two tails (TT):
• P(TT) = (1/2) * (1/2) = 1/4

3-Coin Toss Probability

In a 3-coin toss scenario, there are eight possible outcomes: HHH, HHT, HTH, THH, HTT, THT, TTH, and TTT. The probability of each outcome can be calculated as follows:

1. Probability of getting three heads (HHH):
• P(HHH) = (1/2) * (1/2) * (1/2) = 1/8
2. Probability of getting two heads and one tail (HHT, HTH, THH):
• P(HHT) = (1/2) * (1/2) * (1/2) = 1/8
• P(HTH) = (1/2) * (1/2) * (1/2) = 1/8
• P(THH) = (1/2) * (1/2) * (1/2) = 1/8
3. Probability of getting one head and two tails (HTT, THT, TTH):
• P(HTT) = (1/2) * (1/2) * (1/2) = 1/8
• P(THT) = (1/2) * (1/2) * (1/2) = 1/8
• P(TTH) = (1/2) * (1/2) * (1/2) = 1/8
4. Probability of getting three tails (TTT):
• P(TTT) = (1/2) * (1/2) * (1/2) = 1/8

4-Coin Toss Probability

In a 4-coin toss scenario, there are sixteen possible outcomes, and the probability of each outcome can be calculated using the same method as in the 3-coin toss scenario. The probabilities for getting four heads, three heads and one tail, two heads and two tails, one head and three tails, and four tails are all 1/16.

Solved Examples

Example 1: What is the probability of getting at least one head in two coin tosses?

To find the probability of getting at least one head, we can calculate the probability of getting two tails (TT) and then subtract it from 1.

Probability of getting two tails (TT) = (1/2) * (1/2) = 1/4

Probability of getting at least one head = 1 – Probability of getting two tails = 1 – 1/4 = 3/4

Example 2: What is the probability of getting exactly two heads in three coin tosses?

The probability of getting exactly two heads can be calculated as the sum of the probabilities of HHT, HTH, and THH.

P(Exactly two heads) = P(HHT) + P(HTH) + P(THH) = 1/8 + 1/8 + 1/8 = 3/8

These examples demonstrate how to apply the probability formulas for coin toss scenarios. Understanding these fundamental principles of probability is essential for a wide range of applications in mathematics, statistics, and various fields of science.

Coin toss probability is a fundamental concept in probability theory, serving as a building block for more complex probability calculations. Whether you’re studying probability for academic purposes or interested in understanding the likelihood of events in everyday life, mastering the principles of coin toss probability is a crucial step. This guide has provided the formulas and solved examples for 2-coin, 3-coin, and 4-coin toss scenarios, allowing you to apply these concepts in various probability-related situations.