Elitmus
Exam
Numerical Ability
Probability
Find the probability of (x^4)+4 divisible by 5 ?
a) 8/9
b) 2/5
c) 3/5
d) 1/5
Read Solution (Total 10)
-
- 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
- 10 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
- 10 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 - 10 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
- 10 years agoHelpfull: Yes(4) No(15)
- soorrrry !!!!!!!!!!
ans 8/9 hoga damn sure !!! - 10 years agoHelpfull: Yes(3) No(4)
- ans 4/5 hogaa yaar option sure ho ki sahii h??
- 10 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.....
- 10 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 - 10 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
- 10 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 - 10 years agoHelpfull: Yes(0) No(4)
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