A collection of nickels and dimes contains nine more nickels than dimes. If the total value of the collection is $2.25, how many nickels are there?

x = number of dimes

x + 9 = number of nickels {nine more nickels than dimes}

10x + 5(x + 9) = 225 {value of coin times number of coins equals total value}

10x + 5x + 45 = 225 {used distributive property}

15x + 45 = 225 {combined like terms}

15x = 180 {subtracted 45 from both sides}

x = 12 dimes {divided both sides by 15}

x + 9 = 21 nickels {substituted 12, in for x, into x + 9}

there are

**21 nickels**

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