GRE
Exam
Numerical Ability
Probability
a number is a palindrome if it reads the same from left to right n vice versa. E.g: 24742. What is the probability that a 3 digit number chosen at random is a palindrome?
Read Solution (Total 4)
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- 3 digit no means 100 to 999.
so between 100 to 999
101 111 121 131 141 151 161 171 181 191=10
so upto 999 9*10=90
so prob= 90/900=1/10 (since 100 to 999 is 900) - 11 years agoHelpfull: Yes(7) No(0)
- 3 digit no dat means between 100 to 999
case(1). so between 100 to 200
101 111 121 131 141 151 161 191 = 8
as so on upto 999 8*9=72 cases
while total no of cases are 900 (including 100)
so p = 72/900=8/100=2/25 - 11 years agoHelpfull: Yes(0) No(4)
- ans is 1/10.
- 11 years agoHelpfull: Yes(0) No(0)
- num of 3 digit num's are 900
num of 3 digit palindrome num's are : 90 101,111,121, ...191 10 num's
similarly 202,212,...292, ...... 909,919,...999
so total = 9*10 = 90
prob = 90/900 = 1/10
- 11 years agoHelpfull: Yes(0) No(0)
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