A coin is thrown 3 times. What is the probability that atleast one head is obtained?

The easiest way to solve this is to find the probability of the opposite event. The opposite of getting at least one head is getting no heads at all, which means getting three tails.

Each coin flip has a one-half probability of showing tails. For three flips, multiply: one-half × one-half × one-half equals one-eighth. This is the probability of getting all tails.

Subtract this from 1 to find the probability of at least one head: 1 minus one-eighth equals seven-eighths. This means 7 out of 8 possible outcomes have at least one head.