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sue has 100 dimes and quarters. if the total value of the coins is $21.40, how many of each kind of coin does she have?

1 Answer

11 votes

Answer:

Thus, Sue has 24 dimes and 76 quarters.

steps:

Let d be the number of dimes Sue has and let q be the number of quarters As she has 2140 cents total, a dime is worth 10 cents, and a quarter is worth 25 cents, we obtain the following system of equations:

{ d + q = 100

10 d + 25 q = 2140

From the first equation, we have

d = 100 − q

Substituting that into the second equation, we have

10 ( 100 − q ) + 25 q = 2140

⇒ 1000 − 10 q + 25 q = 2140

⇒ 15 q = 1140

⇒ q= 1140 /15 = 76

Knowing that q = 76 we can substitute that value into the first equation to obtain

d + 76 = 100

∴ d = 24

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