Question 835431
Let {{{P}}} be the number of pennies and {{{D}}} be the number of dimes.
1.{{{P+D=52}}}
Also,
{{{0.01P+0.10D=3.40}}}
2.{{{P+10D=340}}}
Subtract eq.1 from eq. 2,
{{{P+10D-P-D=340-52}}}
{{{9D=288}}}
{{{D=32}}}
Then use either equation to solve for P.
{{{P+32=52}}}
{{{P=20}}}
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20 pennies and 32 dimes.