SOLUTION: A jar contains 40 coins consisting of dimes and quarters and having a total value of $4.90. How many of each kind of coin are there?

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Question 52450: A jar contains 40 coins consisting of dimes and quarters and having a total value of $4.90. How many of each kind of coin are there?
Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
Let the amount of dimes that you have=d
Because the rest of the coins are quarters, let the amount of quarters you have=40-d.
These are usually easier to solve in terms of cents instead of dollars to eliminate the decimals.
Quarters are worth 25 cents, so the amount of money in quarters that you have is 25(40-d)
Dimes are worth 10 cents, so the amount of money you have in dimes is 10d
The total amount of money you have is 490 cents.
25(40-d)+10d=490
1000-25d+10d=490 Don't forget to distribute the 25 to the d.
1000+(-25+10)d=490
1000-15d=490
-1000+1000-15d=-1000+490
-15d=-510
-15d/-15=-510/-15
d=34
The amount of dimes is 34.
The amount of quarters is 40-34=6