The probability that a card drawn from a pack of 52 cards will be a king or a diamond, is?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → 4/13
A pack has 4 kings and 13 diamonds, but the king of diamonds is in both groups, so adding 4 and 13 would count it twice. The addition rule takes the overlap away once: \(P(K\cup D)=P(K)+P(D)-P(K\cap D)\).
Cards that are a king or a diamond: \(4+13-1=16\)
Probability, favourable cards out of all 52: \(\displaystyle\frac{16}{52}=\frac{4}{13}\)