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Charlie and the Perplexing Temperature Billboard

The Puzzler


RAY: Here's the answer. The easy part is that the Celsius side lost the minus sign. So if it were 12 degrees Celsius in the morning, it would have to be minus 12. But 12 doesn't work, because to convert Fahrenheit to Celsius, the equation is F equals nine-fifths of C plus 32.

That's one equation. But to solve this puzzler, you need another equation. And here's the other equation: The temperature in degrees Fahrenheit minus 36 is equal to nine-fifths times the negative C temperature, plus 32.

With those two equations, namely:

F = 9/5C + 32 and
F-36 = 9/5 (-C) + 32

You can solve for F, because when you add those two equations together, you get 2F - 36 = 64, or F = 50.

So, 50 degrees Fahrenheit is ten degrees Celsius and 36 less than 50 is 14, which is minus 10 degrees Celsius. Pretty cute, huh? Who's our winner?

TOM: The winner is Jim Stegman from Grand Haven, Michigan, and for having his answer selected at random from among all the correct answers that we got Jim is going to get a 26-dollar gift certificate to the Shameless Commerce Division at cartalk.com.

RAY: Congratulations, Jim!

[ Car Talk Puzzler ]

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