9514 1404 393
Answer:
She should take the penny doubling option
Explanation:
The option for $12 a day will result in a total of $360 after 30 days. The option for a doubling of earnings each day will result in earnings of more than $12 on the 12th day, and a total more than $360 on the 16th day. By the end of the month, the doubling option will have earned a total in excess of $10 million.
The two "calendar" attachments show the day number, the earnings that day, and the accumulated total. The third attachment has a graph of the first few days, showing the "doubling" option quickly exceeds the option for $12 per day, both in daily value and in accumulated value. The accumulated value is shown on the graph.
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Additional comment
As a parent, you need to be wary of promises you can't keep. Not many parents have $10 million laying around ready to give to a child for yard work.
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There's a story of a Chinese ruler who offered a reward of one grain of rice, doubling for each square of the chessboard. The ruler quickly found his offered reward would bankrupt the kingdom. There would need to be 9 quintillion grains of rice on the last square of the board. The total is about 800 times the entire world's rice harvest last year.