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#1045: Pi Over Two Dopes

Original Air Date: 11.06.2010

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This week on Car Talk, trucker Richard has a busted fuel gauge in his 18-wheeler. He's got a trusty stick to help measure the level of fuel in his cylindrical tank, but needs a formula to tell him whether that level means he's got 3/4 of a tank, or is running on fumes. You'd think two MIT grads would be able to help, but, well, you'd be wrong. Happily, Tom and Ray are more on the ball in recommending a snow-worthy vehicle for Gail, her husband, and their 8 kids, and in helping Louann figure out why her Accord smells like burnt toast. Also, why "oil replenishment" is like vacuuming your living room without a bag, and Tommy goes on the rampage against--Gomer Pyle? All this and lots more, this week on Car Talk.

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This Week's Puzzler

Can the sales-kid explain where the dollar missing from the record store register went? Can you?

Last Week's Puzzler

Dave pronounces his nephew's new atomic watch "stupid" for a particular reason. But Dave's nephew proves him wrong. What was Dave wrong about? Find out!

Show Open Topic

Kids say the funniest things... and Tom and Ray have the examples to prove it!

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    Try Excel Solver

    by RuKaz

    My husband and I are an engineer and a rusty mathematician, but we independently came up with roughly the same answer (mine was the more precise 5.9602724...) for the distance from the bottom of the barrel to the fuel level, such that the area of the cross-section of the barrel content is 1/4 that of the cross-section of the full barrel. The length of the cylinder is irrelevant, so we can work with area instead of volume. My husband derived his own equations, and used trial and error to obtain the approximate answer of 5.96, while I used Excel Solver add-in to get the precise answer above. We each ended up with one trigonometric/transcendental equation, and several algebraic ones -- NO calculus!


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