JEE Main202227 Jul 2022Morning ShiftMathematicsProbabilityActual
Let S be the sample space of all five digit numbers. If p is the probability that a randomly selected number from S , is a multiple of 7 but not divisible by 5 , then 9 p is equal to
Options
- A1 . 0146
- B1 . 2085
- C1 . 0285
- D1 . 1521
Correct answer
C. 1 . 0285
Step-by-step solution
Given, five-digit number, So n S = total 5 digit number will be = 9 × 10 4 Now let A : number is multiple of 7 but not divisible by 5 Smallest 5 digit divisible by 7 is 10003 Largest 5 digit divisible by 7 is 99995 Now by using n t h term of A.P formula we have, ∴     99995 = 10003 + n - 1 7 ⇒ n = 12857 Now finding number which is divisible by 35 Again using A.P formula we have, 99995 = 10010 + P - 1 35 ⇒ P = 2572 Now number divisible by 7 but not by 35 are 12857 - 2572 = 10285 So,