Q40 / 75 · JEE Main 2020 (03 Sep Shift 2) · Mathematics

The probability that a randomly chosen 5- digit number is made from exactly two digits is :

  • Correct answer
    A
    135104
  • B
    150104
  • C
    134104
  • D
    121104

Solution

Total number of five-digit numbers are 9104.

Case I : Choosing two non-zero digits i.e. in C29 ways.

So, number of five-digit numbers containing both digits =25-2.

Case II : Choose one non-zero and one zero as digit i.e. in C19 ways.

So, number of five-digit numbers containing one non-zero and one zero both =24-1.

So, favourable number of ways =C2925-2+C1924-1=3630+915=1080+135=1215

Thus, required probability =12159×104=135104.

Hence, the correct answer is option: 'A'.

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