Two unbiased coins are tossed. The probability of getting at least one head is:

When tossing 2 coins, we need to find the probability of getting at least one head.

"At least one head" means 1 head or 2 heads (not all tails).

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When two coins are tossed, all possible outcomes are:

Coin 1: H, Coin 2: H → 2 Heads

Coin 1: H, Coin 2: T → 1 Head

Coin 1: T, Coin 2: H → 1 Head

Coin 1: T, Coin 2: T → 0 Heads

Total possible outcomes $= 4$

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Outcomes with at least one head:

HH → Has at least one head

HT → Has at least one head

TH → Has at least one head

TT → No heads

Favorable outcomes $= 3$

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$\text{Probability} = \dfrac{\text{Favorable outcomes}}{\text{Total outcomes}}$

$\text{Probability} = \dfrac{3}{4}$

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Alternatively, using the complement rule:

$P(\text{at least one head}) = 1 - P(\text{no heads})$

$P(\text{both tails}) = \dfrac{1}{2} \times \dfrac{1}{2}$

$P(\text{both tails}) = \dfrac{1}{4}$

$P(\text{at least one head}) = 1 - \dfrac{1}{4}$

$P(\text{at least one head}) = \dfrac{3}{4}$

Therefore, the probability of getting at least one head is $\dfrac{3}{4}$.