Given: Three friends play an online quiz. Their chances of winning the quiz are 3/8, 3/4 and 3/5 respectively. Formula: P(Event A will occur) = 1 – P(Event A will not occur) Calculation: The probability that at least one of them wins = 1 – (None of them wins) The probability that none of them wins = (5/8) × (1/4) × (2/5) = 1/16 Hence, the probability that at least one of them wins = 1 – 1/16 = 15/16