If you were to dial any 7 digits on a telephone in random order, what is the probability that you will dial your own phone number?
Assume that your telephone number is 7-digits.

• there are 10 digits on a telephone to dial.
  and we wll choose 1 out of 10,,whose probability will be 1/10.
  if my telephone no. is of 7 digitsthen the probability will be 1/(10^7).
  
  therefore the answer is 1/(10^7)
• 14 years agoHelpfull: Yes(12) No(7)
• total number of 7 digit numbers= 99,99,999-9,99,999 = 90,00,000
  own number is any one of the 9000000 seven digit numbers
  therefore;
  probability of dialling one's own number is 1/9000000
• 13 years agoHelpfull: Yes(5) No(1)
• As the number is of 7 digit
  So first number must not be 0 but we may be dial 0 at first
  so the total numbers there can be form = 10*10*10*10*10*10*10=10000000
  
  probability = 1/10000000
• 13 years agoHelpfull: Yes(2) No(1)
• Suitable condition is only 1.
  Total conditions are 9 X 10 X 10 X 10 X 10 X 10 X 10 = 9000000.
  
  I am taking the first digits as 9 because if phone number is
  7 digit is cannot have ZERO at the start. so probablity is :
  1 / 9000000
• 13 years agoHelpfull: Yes(2) No(0)
• ans is 1/(7^7)
  you can dial only one way to call your number out of 7^7 ways
• 14 years agoHelpfull: Yes(1) No(6)
• total number of numbers in a phone =10
  accord to qstn....
  (10c7*7c7)/7!*10c1=1/70
  :c=combination.....
  solve it......get it....1/70
  
• 13 years agoHelpfull: Yes(1) No(1)
• no.of chances of dialing my own no. ---1
  totaol no. of chances -------10*10*10*10*10*10*10=10(power 7)
  because for each digit i hav 10possible digits to dial
• 13 years agoHelpfull: Yes(0) No(0)
• The total number of cases will be 9999999 because it is maximum in 7 digit numbers. Then we get answer is 1/9999999
• 13 years agoHelpfull: Yes(0) No(1)
• ways of choosing 7 digits = 10 * 10 * 10 * 10 * 10 * 10 * 10 = 10^7
  our no is one of these
  So, ans is (1/10^7)
• 13 years agoHelpfull: Yes(0) No(1)
• we have our favorable outcome as only one correct number
  but there are ten digit which can be selected in 10C7 ways
  so probabilty is =1/10C7
• 13 years agoHelpfull: Yes(0) No(0)
• 10*10*10*10*10*10*10=10^7
• 13 years agoHelpfull: Yes(0) No(0)
• Ans. 1/9000000
  
  First digit of telephone number cannot be zero. therfore its probability is 1/9.
  All other digits of telephone number have the probability 1/10.
  Therefore probability of my phone numbers is (1/9)*(1/10)*(1/10)*(1/10)*(1/10)*(1/10)*(1/10) = 1/9000000
• 13 years agoHelpfull: Yes(0) No(0)
• 1 in 823543 my logic is 7 to the seventh power so its 7x7x7x7x7x7x7=823543
• 13 years agoHelpfull: Yes(0) No(0)