Given: A box contains 25 balls bearing numbers 1 , 2 , 3 , 4 _________ 25. Formula used: Probability(P) = (Number of required outcomes)/(Total number of outcomes) Calculations: Total number of outcomes = 25 Number of required outcomes = 8 (5, 7, 10, 14, 15, 20, 21, 25) ⇒P=8/25 ∴ The probability of number on the picked ball is divisible by 5 or 7 is 8/25.