If 'n' integers taken at random and multiplied together, then what is the probability that the last digit of the product is 1, 3, 7 or 9 ?


1) 2 n⁄ 5 n
2) 4 n - ( 2 n &
3) 4n⁄ 5n
4) None of these

• 2n/5n
  as number of digits at end can b 0 to 9
  and here it is asked only for 4 digits
  so, 4/10 is equal to 2/5
  
• 10 years agoHelpfull: Yes(29) No(1)
• 2/5 i.e. option 1
  There are 10 possibilities of last digit (0 to 9)
  No. of digits asked for= 4
  Reqd. Probability= 4/10= 2/5= 2n/5n
• 10 years agoHelpfull: Yes(5) No(0)
• last digit of product:
  1,3,7,9
  means there are four way out of 10(Product can be end with 0....9)
  =(4/10)^n=(2/5)^n
  Ans:2^n/5^n
• 9 years agoHelpfull: Yes(3) No(1)
• multiplied together means if we choose n then the corrwsponding number we are getting is n^2.
  but 3 and 7 can not be the unit digit of a square number,
  so the answer should be 2/10=1/5
• 9 years agoHelpfull: Yes(0) No(1)