Question

An unbiased coin is tossed once. What is the complement of the following event X
X = {coin shows heads}

• A. Coin shows either heads or tails
• B. Coin shows heads and tails
• C. Coin shows tails
• D. None of the above

Answer 1

The correct option is C Coin shows tails

First let’s decide what will be the sample space of the experiment of tossing a coin once. It will be {H, T} as either head comes up or tails comes up.
So S = {H,T}
Now X = {H}
X’ or complement of X is everything in sample space except Heads.
So X’ = {H,T} - {H}
= {T}