
Mark M. answered 01/27/18
Tutor
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Mathematics Teacher - NCLB Highly Qualified
Sn = a1(1 - rn) / (1 - r) Learn it or know where you can find it!
n = 12 (look at the clock
S12 = 1(1 - 212) /(1 - 2)
Can you calculate and answer?