Three coins are tossed together. Find the probability of getting at most two heads.

Given:

Three coins are tossed together.

To do:

We have to find the probability of getting at most two heads.

Solution:

When three coins are tossed, the total possible outcomes are HHH, HHT, HTH, THH, TTH, THT, HTT and TTT.

This implies,

The total number of possible outcomes $n=8$.

Number of outcomes where at most two heads occur $=7$    (Except TTT) 

Total number of favourable outcomes $=7$.

We know that,

Probability of an event $=\frac{Number\ of\ favourable\ outcomes}{Total\ number\ of\ possible\ outcomes}$

Therefore,

Probability of getting at most two heads $=\frac{7}{8}$

The probability of getting at most two heads is $\frac{7}{8}$.