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Q. In an A.P. of positive integers, Tn = (66541)^8768, if d=9, find a????
a.0
b.1
c.6
d.7

[administration]

For an AP, T_n=a+(n-1)d
so its clear that, Tn=a(mod d)
Considering above question, Tn=a(mod 9)
So if we find  the remainder of  (Tn/9), we get the first term
66541=4(mod 9)
4⁸⁷⁶⁸=(4³)²⁹²² x 4²=1×16(mod 9)=7(mod 9)
Hence a = 7 Ans.

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