Probability-Digits-from-1-to-9-are-randomly-placed-to-form-a-9-digit-number-What-is-the-probability-that-the-number-is-divisible-by-18-

Question Number 135861 by liberty last updated on 16/Mar/21

P r o b a b i l i t y

Digits from 1 to 9 are randomly placed to form a 9-digit number. What is the probability that the number is divisible by 18?

Answered by EDWIN88 last updated on 16/Mar/21

To be divisible by 18, the number must be

divisible by 2 and 9 . The sum of digits is

1 + 2 + 3 + 4 + \dots + 9 = \frac{9 \times 10}{2} = 45 which is

divisible by 9, There are 9 digits of which are

even (2, 4, 6, 8) . So the probability that the

number is divisible by 18 is \frac{4}{9}

Facebook Tweet Pin