SOLUTION: A merchant doing business in Lucca doubled his money there and then spent 12 denarii. On leaving, he went to Florence, where he also doubled his money and spent 12 denarii. Retur

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Question 1029395: A merchant doing business in Lucca doubled his money there and then spent 12
denarii. On leaving, he went to Florence, where he also doubled his money and
spent 12 denarii. Returning home to Pisa, he there doubled his money and again
spent 12 denarii, nothing remaining. How much did he have in the beginning?
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Let's say he starts with X.
In Lucca, the total changed to,
T%5B1%5D=2X-12
In Florence,
T%5B2%5D=2T%5B1%5D-12=2%282X-12%29-12=4X-24-12=4X-36
In Pisa,
T%5B3%5D=2T%5B2%5D-12=2%284X-36%29-12=8X-72-12=8X-84
8X-84=0
8X=84
X=84%2F8
X=10%261%2F2 denarii