Brine Tank

A 700 gallon tank has 600 gallons of salt water in it; the amount of salt dissolved in the water is a half-pound per gallon. An intake valve is opened and another 100 gallons of brine is allowed to flow into the tank; this brine has 2 pounds of salt per gallon. The tank is now full. Its contents are thoroughly stirred, and then an outlet valve is opened and 100 gallons of the mixture are drained out. This process is repeated two more times. At the end, how much salt per gallon is in the 600 gallons that remain in the tank?

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Tape Sale

Back in the day of analog recording tape, Amalgamated Grissom Enterprises had a sale. Professional quality tape dropped from $30 to $28 per reel, and regular quality tape dropped from $24 to $23 per reel. The Bethel Recording Studio normally spent $1440 per week on tape, 3/4 of which was used for professional quality tape. How much did they save during each week of the sale?

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Day Before Yesterday

What day of the week is it if the following statement is true?

When the day before yesterday was referred to as the day after tomorrow, the day that was then called “yesterday” was as far away from the day we now call “tomorrow” as yesterday is from the day on which we shall be able to speak of last Monday as “a week ago yesterday.”

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