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Real-Life Activities

Real-Life Math -- Solution

You are a clown using cards as a part of your act, and are trying to stack your cards so that you can predict the outcome of your tricks.

  1. You have a stack of cards: 13 with diamonds, 13 with clubs, 13 with spades and 13 with hearts. What is the probability that someone in your audience will flip up a card with a heart, a diamond, a spade or a club?

    Total number of cards: 13 +13 +13 + 13 = 52
    Divide the total number of each suit by the total number of cards to figure out the probability:

    Diamonds: 13/52 = 1/4
    Spades: 13/52 = 1/4
    Clubs: 13/52 = 1/4
    Hearts: 13/52 = 1/4

    For each suit, the probability that it will be flipped over is 1 in 4.

  2. You take out all the clubs and substitute them with 13 more hearts. Now what is the probability that an audience member will flip up a heart?

    Total number of hearts = 13 from original pack + 13 new hearts = 26 hearts
    Total number of cards = 0 clubs + 26 hearts + 13 diamonds + 13 spades = 52 cards

    Probability:
    26 hearts / 52 total cards = 1/2
    The probability that an audience member will now pick a heart is 1 in 2.

"Clowns also use math to run their businesses, to fill out invoices [and] to pay taxes," says Levene. "But that's not really the fun stuff!"