Find the probability of (x^4)+4 divisible by 5 ?
a) 8/9
b) 2/5
c) 3/5
d) 1/5

• for the divisibility of y by 5 the last digit should be either 0 or 5
  the equation y=x^4+4 it will divisible by 5 if last digit will be 0 or 5
  so it will happen when the x^4 either 1 or 6
  for 1 it should be 1^4,3^4,7^4,9^4
  and for 6 it should be 6^4,4^4,8^4,2^4
  so sample set should be {0,1,2,3,4,5,6,7,8,9,}
  and event set is {1,2,3,4,6,7,8,9}
  so probability is
  8/10=4/5 ans
  
  
  
• 9 years agoHelpfull: Yes(43) No(5)
• answer is 8/9 because in x =1,2,3,4,6,7,8,9 satisfy that equation only 5 not satisfy that equation so answer is 8/9
• 9 years agoHelpfull: Yes(12) No(3)
• ans= 4/5
  
  for div by 5 unit digit shud b 5 or 0
  
  for 0, x can b 2, 4,,6,8,12,14,16,18......like that total 40 values for x
  
  for unit digit 5 x can be 1, 3, 7,9,11,13,17,19....like 40 values
  
  so in 100 total possible values for x are 80
  
  prob=80/100=4/5
• 9 years agoHelpfull: Yes(6) No(4)
• guys there was one more condition in this question that x is a 4digit no
  for the divisibility of y by 5 the last digit should be either 0 or 5
  and the equation says (x^4)+4 =5
  it means the last digit can not be zero boz 0+4 will lead to last digit 4 which is not divisible by 5
  so the last digit of x^4 should be 1
  and only 1^4 3^4 7^4and 9^4 satisfies the condition
  so the sample set s=0,1,2,3,4,5,6,7,8,9.
  n(s)=10
  and event set =1,3,7,9
  n(e)=4
  so the probability will be n(e)/n(s)=4/10=2/5
  so 2/5 is answer
  
• 9 years agoHelpfull: Yes(4) No(15)
• soorrrry !!!!!!!!!!
  ans 8/9 hoga damn sure !!!
• 9 years agoHelpfull: Yes(3) No(4)
• ans 4/5 hogaa yaar option sure ho ki sahii h??
• 9 years agoHelpfull: Yes(1) No(0)
• i think 8/9 is right one..... becoz 0 to 9 only x=5 is there which is nt divided by 5.....
• 9 years agoHelpfull: Yes(1) No(3)
• Oshank Karn here one more condition apply
  for the divisibility of 5 unitary digit should be 0 or 5
  and our eq is x^4 +4 =5
  it means the last digit should be 1 or 6
  for 1 it should be 1^4,3^4,7^4,9^4
  and for 6 it should be 6^4,4^4,8^4,2^4
  so sample set should be {1,2,3,4,5,6,7,8,9,}
  and event set is {1,2,3,4,6,7,8,9}
  so probability is 8/9
• 9 years agoHelpfull: Yes(1) No(3)
• chances of last digit being 0 , 5 will fail only in case of any number^4+4 except last digit containing 0,5 is divisible by 5 8/9 is the best answer
• 9 years agoHelpfull: Yes(1) No(2)
• C 3/5
  x=0-9
  and find the unit digit for every value of x and add 4 , then chk it is divisible by 5 or not
  so we have find 6 value 0,1,3,6,7,8 which r divisible by and total is 10(0-9) so
  6/10=3/5
• 9 years agoHelpfull: Yes(0) No(4)