SOLUTION: This is a question I REALLY don't understand I hope you might be able to help me. "Carey has $2.55 made up of pennies, dimes and quarters. She has as many dimes as pennies and s

Algebra ->  Customizable Word Problem Solvers  -> Coins -> SOLUTION: This is a question I REALLY don't understand I hope you might be able to help me. "Carey has $2.55 made up of pennies, dimes and quarters. She has as many dimes as pennies and s      Log On

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Question 23107: This is a question I REALLY don't understand I hope you might be able to help me.
"Carey has $2.55 made up of pennies, dimes and quarters. She has as many dimes as pennies and she ahs eighteen coins in all. How many quarters does she have?"
Well I tried this way but It didn't work and I'll show you
Let x = pennies 0.01x
x = dimes 0.1x
18 - x = 0.25 (18 - x)
And I wrote as this way
0.01x + 0.1x + 0.25(18 - x) = $2.55
You think you can tell me what I did wrong?
Found 2 solutions by venugopalramana, stanbon!:
Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
SEE MY COMMENTS BELOW

"Carey has $2.55 made up of pennies, dimes and quarters. She has as many dimes as pennies and she ahs eighteen coins in all. How many quarters does she have?"
Well I tried this way but It didn't work and I'll show you
Let x = pennies...GOOD..BETTER WRITE ITS VALUE IN $= 0.01x
x = dimes...GOOD...AGAIN BETTER WRITE ITS VALUE IN $= 0.1x
18 - x = 0.25 (18 - x)...NO..NO..YOU MADE A SIMPLE MISTAKE..BETTER GO STEP BY STEP.
TOTAL NUMBER OF COINS =18
NUMBER OF DIMES =NUMBER OF PENNIES =X...SO NUMBER OF PENNIES AND DIMES =X+X=2X..HENCE
NUMBER OF QUARTERS =18-2X...ITS VALUE IS 0.25(18-2X)
And I wrote as this way
0.01x + 0.1x + 0.25(18 - x) = $2.55...GOOD BUT CORRECT THE MISTAKE GIVEN ABOVE
0.01X+0.1X+0.25(18-2X)=2.55
0.11X+4.5-0.5X=2.55
4.5-2.55=0.5X-0.11X=0.39X
1.95=0.39X
X=1.95/0.39=195/39=5
SO THERE ARE 5 PENNIES ,5 DIMES AND 8 QUARTERS
SO GOT IT ..YOU DID VERY WELL KEEP IT UP AND IMPROVE ON YOUR MISTAKES

You think you can tell me what I did wrong?

Answer by stanbon!(97) About Me  (Show Source):
You can put this solution on YOUR website!
You did fine till you got to the equation.
You have x pennies and x dimes so you must have (18-2x) quarters.
Make that change and I think everything will turn out right.
Cheers,
stan H.