Question 847578
p pennies
n nickels
d dimes
q quarters


{{{0.01p+0.05n+0.10d+0.25q=1.10}}} and {{{p+n+d+q=7}}}.
The money count equation can also be stated as {{{p+5n+10d+25q=11}}}. 
That is FOUR unknown variables and only TWO equations.  Are you given any more information in the description?  Are you expecting a counting principles or discrete type of analysis?  


How about 3 quarters and 1 nickel and 3 dimes?  I found this by first setting number of quarters to 4, and found I could not quickly find a good intuitive combination of dimes and nickels; so I chose to try 3 quarters, and went a little up and down with nickels and dimes, and found that given combination: 3 quarters, 1 nickel, 3 dimes.