SOLUTION: piggy bank consists of nickels and dimes. there are 30 coins worth $1.90, how many nickels and dimes are in the piggy bank

Algebra ->  Customizable Word Problem Solvers  -> Coins -> SOLUTION: piggy bank consists of nickels and dimes. there are 30 coins worth $1.90, how many nickels and dimes are in the piggy bank      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 940790: piggy bank consists of nickels and dimes. there are 30 coins worth $1.90, how many nickels and dimes are in the piggy bank
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
piggy bank consists of nickels and dimes. there are 30 coins worth $1.90, how many nickels and dimes are in the piggy bank 
Let the number of nickels be x
Then the number of dimes, using 
ONE PART = TOTAL MINUS OTHER PART,
is 30-x.  
                      Value      Value
Type       Number       of         of
 of          of        EACH       ALL
coin        coins      coin      coins
-------------------------------------------
NICKELS      x        $0.05    $0.05x 
DIMES      30-x       $0.10    $0.10(30-x)
-------------------------------------------
TOTALS      30        -----    $1.90

 The equation comes from the column on the right

  %28matrix%284%2C1%2CValue%2Cof%2CALL%2Cnickels%29%29%22%22%2B%22%22%28matrix%284%2C1%2CValue%2Cof%2CALL%2Cdimes%29%29%22%22=%22%22%28matrix%284%2C1%2CTotal%2Cvalue%2Cof%2Ccoins%29%29

0.05x + 0.10(30-x) = 1.90

Get rid of decimals by multiplying every term by 100

     5x + 10(30-x) = 190

    5x + 300 - 10x = 190

         -5x + 300 = 190

               -5x = -110

                 x = 22 = the number of nickels

The number of dimes is 30-x or 30-22 or 8 dimes.

Checking:  22 nickels is $1.10 and 8 dimes is $0.80

And indeed $1.10+$0.80 = $1.90.

Edwin