The probability of getting at least one head when three coins are tossed simultaneously is $\frac{7}{8}$. This is because there are eight possible outcomes when three coins are tossed, and only one of these outcomes (all tails) results in no heads. The other seven outcomes all result in at least one head.
To calculate the probability of getting at least one head, we can use the following formula:
$$P(\text{at least one head}) = 1 – P(\text{all tails})$$
P(all tails) is the probability of getting three tails when three coins are tossed. This can be calculated as follows:
$$P(\text{all tails}) = \frac{1}{2} \times \frac{1}{2} \times \frac{1}{2} = \frac{1}{8}$$
Therefore, the probability of getting at least one head is:
$$P(\text{at least one head}) = 1 – \frac{1}{8} = \frac{7}{8}$$