Real-Life Treasure Hunt

You never know what's buried right under your feet. One California couple saw a can sticking out of the ground, so they dug and dug, and found eight cans filled with 1,427 gold coins! The mix of $5 coins, $10 coins and $20 coins have a total face value of almost $28,000. But these coins are worth far more than that, because the older a coin, the fewer of that coin we still have, which makes it more special - and valuable!

Wee Ones: Which has a bigger number on it, a $5 coin or a $10 coin?

Little Kids: If you found two $5 coins, how much money would you have?
Bonus: If the coins are worth $10 million total and just 1 of them is worth $1 million, how much are the others worth all together?

Big Kids: If you pulled out a $5 coin, then a $10, then a $20, then a $5 again to repeat the pattern...how much would the first 6 coins be worth together?
Bonus: If the couple buried the 1,427 coins again in bags, with at most 100 coins in each, at least how many bags would they need?

The Sky's the Limit: If there were equal numbers of $20s, $10s and $5s, how many of each would you need for the face value to add exactly to $28,000?

Answers:

Wee Ones: A $10 coin.

Little Kids: $10.
Bonus: $9 million. 

Big Kids: $70.
Bonus: At least 15 bags. 

The Sky's the Limit: One trio of a $20 coin, a $10 and a $5 adds up to $35, so you just need to find out how many sets of $35 go into $28,000 -- and you can guess it will go evenly, since both are divisible by 7! 8 sets of $35 are worth $280, and you need 100 times as much as that, so you need 800 of each coin.

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