<PRE><B>Question 1040145</B>
murtha has decided to start a pebble collection. she collects one pebble the first day and two pebbles on the second day. on each subsequent day she collects one more pebble than the previous day. how many petals will she have collected at the end of the 12th day? 
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2^0 + 2 + 2^2 + 2^3 +...+ 2^11
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Geometric sequence with a = 1, r = 2, and n = 12
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S(12) = a[(r^n - 1)/(r-1)] = 1[2^12 - 1]/1 = 4095 pebbles
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Cheers,
Stan H.
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