Question 129932
Jim has a total of 50 coins. Some are nickels and some are dimes. altogether he has $4.15. How many dimes does he have? How many nickels?*********** 

Than is states that I have to cheack it! 
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Let the # of nickels be "x" ; value of these is 5x cents
# of dimes is "50-x" ; value of these is 10(50-x) = 500-10x cents
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EQUATION:
value + value = 415 cents
5x + 500-10x = 415
-5x = -85
x = 17 (# of nickels: worth 5*17 = 85 cents)
50-x = 33 (# of dimes; worth 10*33 = 330 cents)
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Checking:
85 cents + 330 cents = $4.15 
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Cheers,
Stan H.