If three unbiased coins are tossed, then what is the probability of getting one or more heads is

The odds would be 7/8 that at least one would be a heads.

Step-by-step explanation:

To find your answer, see each coin flip as unrelated to the last one.

For the first coin flip, you can either get heads or tails. So, there's only 2 possible outcomes.

Flip 1 (Outcome 1) : H or T

Flip 1 (Outcome 2) : H or T

But when it comes to the second flip, now each outcome has two possible "sub-outcomes" of their own. So there's now four total outcomes.

Flip 2 (Outcome 1) : H, H

Flip 2 (Outcome 2) : H, T

Flip 2 (Outcome 3) : T, H

Flip 2 (Outcome 4) : T, T

On the third flip, there would now be 8 outcomes. As each "sub-outcome" has own of their own.

Flip 3 (Outcome 1) : H, H, H

Flip 3 (Outcome 2) : H, H, T

Flip 3 (Outcome 3) : H, T, H

Flip 3 (Outcome 4 : H, T, T

Flip 3 (Outcome 5) : T, H, H

Flip 3 (Outcome 6) : T, H, T

Flip 3 (Outcome 7) : T, T, H

Flip 3 (Outcome 8) : T, T, T

So all but one of the eight outcomes have at least one heads drawn. Due to this, the odds of an heads happening would be 7/8 within all of the possible outcomes.