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coin combinations

  1. math_celebrity

    Marissa has 24 coins in quarters and nickels. She has 3 dollars. How many of the coins are quarters?

    Let n be the number of nickels and q be the number of quarters. We have two equations: (1) n + q = 24 (2) 0.05n + 0.25q = 3 Rearrange (1) to solve for n in terms of q for another equation (3) (3) n = 24 - q Plug (3) into (2) 0.05(24 - q) + 0.25q = 3 Multiply through: 1.2 - 0.05q + 0.25q = 3...
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