Question 542082
"So far I have done: Dimes=x" this part is right, though I like to use D for dimes
"Nickels=2x" Again, right.
"Quarters=(31-x)" This is wrong. What you are saying with this equation is that {{{Quarters=31-Dimes}}}. But what about the nickels? should be:
{{{Q=31-d-n=31-d-2d=31-3d}}} or in your case
{{{Q=31-3x}}}
.
"Dimes= 10 times x" Correct
"Nickels= 5 times 2x" Correct
"Quarters= 25 (31-x)" Use above formula.
{{{Q=25*(31-3x)}}}
And solving:
{{{10x+5*2x+25*(31-3x)=280}}}
{{{10x+10x+775-75x=280}}}
{{{-55x=-495}}}
{{{x=9}}}
And I believe you've got it from here! Hope this helps