Someone tossed 4 coins.

What is the probabilty that he will get exactly 3 tails when he tosses the 4 coins?

Guest Jan 29, 2022

edited by
Guest
Jan 29, 2022

#1**+5 **

There are actually many ways to solve this problem, but I will show you one I like the best:

There are 2 * 2 * 2 * 2 = 16 possibilities.

We can have 4 possibiltiies that satisfy the problem:

TTTH

TTHT

THTT

HTTT

Thus the answer is 4/16 = **1/4**.

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ShockFish

ShockFish Jan 30, 2022

#2**+2 **

\({1 \over 2^3} \times {1 \over 2} \times {4 \choose 1} = {4 \over 16} = \color{brown}\boxed {1\over 4}\)

Explanation:

There is a \({1 \over 2} \times {1 \over 2} \times {1 \over 2} \) chance of the successes (\(3\) tails)

There is a \(1 \over 2\) chance of failure (\(1\) head)

There are \(4 \choose 1\) ways to order the failure (the same as \(4 \choose 3\), which counts the ways to order the successes.)

BuilderBoi
Feb 1, 2022