SOLUTION: Rob has 40 coins, all in dimes and quarters, worth $7.60. How many of each coin does he have?

Question 1054449: Rob has 40 coins, all in dimes and quarters, worth $7.60. How many of each coin does he have?
Answer by ikleyn(52814) (Show Source): You can put this solution on YOUR website!
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Rob has 40 coins, all in dimes and quarters, worth $7.60. How many of each coin does he have?
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Let d = the number of dimes.
Then the number of quarters is (40-d).

The dimes contribute 10d cents to the total.
The quarters contribute 25*(40-d) cents to the total.

The "value" equation is

10d + 25*(40-d) = 760.

Simplify and solve for x:

10d + 1000 - 25d = 760,   or

-15d = 1000-660  --->  -15d = -240.

d =  = 16.

Answer.  16 dimes  and  40-16 = 24 quarters.

There is entire bunch of the lessons on coin problems
    - Coin problems
    - More Coin problems
    - Solving coin problems without using equations
    - Kevin and Randy Muise have a jar containing coins
    - Typical coin problems from the archive
    - More complicated coin problems
    - OVERVIEW of lessons on coin word problems
in this site.

Read them and become an expert in solution of coin problems.

Also, you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this online textbook under the topic "Coin problems".

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