Question 757601
p for pennies
n for nickels
d for dimes
c for quarters (because lower Q looks like a 'nine')


c=13, and n=5.
p=2d for "twice as many pennies as dimes".


Account for the money in the jar:
{{{highlight(0.01p+0.05n+0.10d+0.25c=4.58)}}}
{{{0.01*2d+0.05*5+0.1*d+0.25*13=4.58}}}
{{{0.01*2d+0.1*d=4.58-0.05*5-0.25*13}}}
{{{(0.02+0.1)d=4.58-.25-3.25}}}
{{{0.12d=4.58-3.50=1.08}}}
{{{d=1.08/0.12}}}
{{{highlight(d=9)}}}
and you can use it to find the number of pennies.