S is the infinite sequence S1 = 2, S2 = 22, S3 = 222,...Sk = Sk–1 + 2(10k–1). If p is the sum of the first 30 terms of S, what is the tenth digit of p, counting right to left from the units digit?  Choose the correct choice:  A) 1  B) 2  C) 4  D) 6  E) 9
C   Sum of unit digits of first 30 terms = 60   Sum of tens digits of first 30 terms = 58   Sum of thousands digits of first 30 terms = 56   and so on..   p1 = 0   p2 = (6+58) = 4   p3 = (6+56) = 2   p4 = (6+54) = 0   p5 = (6+52) = 8   p6 = (5+50) = 5   p7 = (5+48) = 3   p8 = (5+46) = 1   p9 = (5+44) = 9   p10= (4+42) = 6   ANSWER : 6
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S is the infinite sequence S1 = 2, S2 = 22, S3 = 222,...Sk = Sk–1 + 2(10k–1). If p is the sum of the first 30 terms of S, what is the tenth digit of p, counting right to left from the units digit?