Quant Probability Quant PnC

If a 4 digit number is formed with digits 1, 2, 3 and 5. What is the probability that the number is divisible by 25, if repetition of digits is not allowed?

  1. 1/12
  2. 1/6
  3. 1/8
  4. 1/4

Answer

The total number of four-digit numbers that can be formed = 4!.

If the number is divisible by 25, then the last two digits must be 25.

So the first two digits can be arranged in 2! ways.

Hence, probability = 2!/4! = 1/12

The correct option is A.