7-11, A MATHEMATICAL PUZZLEA customer walks into a 7-11 store and picks up four items.-- How much do I pay? -- she asks. The clerk punches a few numbers on a calculator as the customer watches on. -- That will be exactly $7.11 The customer raises her brows. -- Excuse me but didn't you just MULTIPLY the four prices, instead of adding them...? -- Oh, yes, I'm sorry! Just a minute... -- says the clerk and this time adds the prices. -- Here it is... $7.11 -- ??? -- Your four items add up to $7.11. -- Well, here it is, but I guess I'll have to check myself ... -- Sure, if anything is wrong please come back. -- What are your opening hours? -- 7-11. [A long time ago 7-11 stores were open from 7am to 11pm.] QUESTION 1: What were the prices? QUESTION 2: Could that mistake have occurred with fewer or more than 4 items?
|
Those who solved the puzzle first (Andreas Andersson and Luiz Borgonovo) received a free lunch, worth... $7.11