Question 1041582
Joe decided to start a penny collection. He starts his collection with one penny on the first day, then two pennies on the second day, then four pennies on the third day, and then eight pennies on the fourth day. 
Assume this pattern continues and determine the total size of Joe's penny collection on the 15th day.
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Use days 0 to 14:
Day 0 - 1
Day 1 - 2
day 2 - 4
.
.
.
Day 14 - 16384  (2^14)
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Add them --> 2^15 - 1
= 32767 pennies.