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by kvcpk » Fri Jul 16, 2010 4:06 am
pradeepkaushal9518 wrote:A palindrome is a number that reads the same forward and backward, such as 121. How many odd, 4-digit numbers are palindromes?


40
45
50
90
2500
Number of positions to be filled is 4.
Numbers that can fill each position are 10 (0-9)

NOw we know that the number is odd.
Hene First position can be filled by (1,3,5,7,9) [5 ways - this will be same as last position]
Now, second position can be filled in 10 ways [0-9] - this will be same as third position.]

Hence count = 5*10 = 50
pick C.

Whats OA?
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by pradeepkaushal9518 » Fri Jul 16, 2010 4:13 am
correct praveen u have given same explanation as given by the mgmat
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by kvcpk » Fri Jul 16, 2010 4:15 am
pradeepkaushal9518 wrote:correct praveen u have given same explanation as given by the mgmat
good to hear that :)
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