Question 1034000
 If a jar contains 21 coins, all of which are either nickles or dimes . And the total value is $1.75 , how many coins of each are in the jar? 
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Quantity:: n + d = 21 coins
Value:::: 5n + 10d = 175
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Modify for elimination::
n + d = 21
n + 2d = 87.5
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Subtract and solve for "d":
d = 66.5
Note:: d must be a positive whole number.
Please check your post.
Cheers,
Stan H.