ShmoopTube

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Here's a shmoopy question for you...

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The following fair spinner is spun one time.

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According to Norse legend, God spins it every time a new human child is born,

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to determine whether they're going to be a winner... or a loser.

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Aw, and you thought we had free will.

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What is the probability that the pointer creates a new... winner?

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And here are the potential answers...

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OK, that FAIR spinner thing again.

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For these kinds of problems, FAIR just means that what you see is what you get...

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...that is, the drawing is drawn to scale and the spinner isn't a Las Vegas scam to

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cheat widows out of their savings by always landing on LOSE.

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It's an odds or probability question -- but it's kind of a trick question as well.

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Just look at the wheel. The total real estate taken up by "WIN" is ... large.

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Like... "clearly over half" large.

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Now look at the answers. Anything, uh.. stand out?

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Yeah -- it's D.

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No other answer could POSSIBLY work. It's D. We can just click it and move on.

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Go ahead. Don't be shy. There's nothing wrong with using common sense.

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BUT let's assume for a second that we actually want to learn how to solve this problem...

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If we really wanted to get fancy, there's a few big fat clues here,

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the biggest of which is the presence of right angle.

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We know that a right angle is 90 degrees and

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is a quarter of a circle... or 25% of it.

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And that right angle is bisected with this line. That is, it's cut in half.

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So each of these tiny slices is 12.5% of the circle or 45 degrees.

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We have 3 LOSES of 12.5% which total to 37.5%.

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The wins then have to be 100-37.5% or 62.5%.

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We made the calculation but... we really didn't have to.

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In fact, wasting so much time makes us feel like a real loser.

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Wait a minute...

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