Question 131307
Number of nickels:  n
Number of dimes: d
Total number of coins: 12, so {{{n+d=12}}}, in other words, {{{n=12-d}}}


Total value of n nickels is 5n cents.
Total value of d dimes is 10d cents.
Total money collected is {{{5n + 10d=95}}}, but since {{{n=12-d}}}


{{{5(12-d)+10d=95}}}
{{{60-5d+10d=95}}}
{{{5d=35}}}
{{{d=7}}}  and {{{n=12-7=5}}}


Check:
7 dimes is worth 70 cents
5 nickels is worth 25 cents
70 plus 25 is 95.  Answer checks.