Question 12099
she has 3 more nickles than quarters=x+3
quarters=x
she has two times as many dimes as quarters=2x


nickles:  multiply (x+3)by (.05)
quarters:  multiply (x) by (.25)
dimes:  multiply 2x by .10



(x+3)(.05)+(x)(.25)+(2x)(.10)=3.15
0.05x+0.15 +0.25x+0.20x=3.15
0.50x+0.15=3.15         <--subtract both sides by .15
(0.50x+0.15)-0.15=(3.15)-0.15 
0.50x=3    <--divide both sides by .5
{{{0.50x/.5}}}={{{3/.5}}}
x=6


since quarters=x, and x=6 she has 6 quarters
nickles=x+3=6+3=9 nickles
dimes=2x=2(6)=12 dimes



check:  6($0.25)+9($0.05)+12($0.10)
$1.50+$0.45+$1.20=$3.15