Question 1205779

<pre>
WHICH COIN-TYPE   COUNTofCOINS      REMOVE-THESE        REMOVED-MONEYDollars
       5c             2x                  x                 0.05x
      10c             6x                 3x                 0.10*3x
      20c             7x
                  -------------                         ----------------------
                     15x                                    4.20
</pre>



{{{0.05x+0.10*3x=4.2}}}

-

{{{0.35x=4.2}}}

{{{x=4.2/0.35}}}

{{{x=12}}}

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