Question 1006288
3,9,27,81,243,729...
it repeats after every fourth term.
Therefore, 2004 is a fourth term exponent, and the ones digit is 1.
D
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The middle of this series is 100/2, between the 50th term 99/2 and 51st 101/2
There are 100 terms, so 100/2*(100)=5000
A.