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I came across a little puzzle today and I thought it was really neat:

A customer walked into a 7-11 store and decided to buy four items. When he brought his items to the check-out counter, the cashier rang in the purchases and told the customer that the cost was $7.11. The customer was curious that the cost of his items was the same as the store name, so he asked the clerk how he came to that price. The clerk responded that he had simply multiplied the prices of the four individual items. The customer protested! He insisted that the four prices should have been added, not multiplied. The clerk said that it was okay with him, but, that the total was still the same: exactly $7.11.

What were the prices of the four items?








The prices for the 7-11 problem are: $1.20, $1.25, $1.50, and $3.16

$7.11 is not the only number which works. There are many other prices which have this property such as $6.93, $11.40, but I guess $7.11 became so popular because of the store with the same name. Note that $7.11 has a single, unique solution, while this is not necessarily true of other prices with this property. Also there are approximate solutions for $7.11 such as $1.01, $1.15, $2.41, and $2.54. These sum to $7.11 but the product is 7.1100061.

I'm not really sure how the solutions are obtained, but I am currently looking for it. If you have any idea, please /msg me or add it below.