Question 893983
The quantity of all coins is 33.
The amount of money for this combination of coins is $2.40.


ASSIGN VARIABLES
p = how many pennies
d = how many dimes
q = how many quarters


EQUATIONS
p=d, "the pennies and dimes are equal".
p+d+q=33, account for how many coins
0.01p+0.10d+0.25q=2.40, account for the amount of money value


Can you simplify and solve the system of equations?
{{{highlight_green(system(p=d,p+d+q=33,0.01p+0.10d+0.25q=2.40))}}}


SOME STEPS TO BEGIN SOLVING THE SYSTEM

Simplify the money count equation using dividing both sides by 0.01, so you will have whole number coefficients.
{{{p+10d+25q=240}}}.

You can use the p=d equation to eliminate either of these variables in the coin count and money count (now simplified) equations.  Here, I choose substituting for p...
{{{(d)+d+q=33}}}, giving {{{2d+q=33}}}.
{{{(d)+10d+25q=240}}}, giving {{{11d+25q=240}}}.
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Now you have a simplified system in the variables d and q:
{{{highlight_green(system(2d+q=33,11d+25q=240))}}}.
FINISH SOLVING THIS SYSTEM.