Question 831749
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number of 10 centavo coins = n</pre>the number of 25 centavo coins is four more than thrice the number of 10 centavo coins<pre>number of 25 centavo coins = 3n+4</pre>total of php 120.<pre>

0.10n + 0.25(3n+4) = 120
    10n + 25(3n+4) = 12000 
     10n + 75n+100 = 12000
           85n+100 = 12000
               85n = 11900   
                 n = 140 centavo coins

number of 25 centavo coins = 3n+4 = 3(140)+4 = 420+4 = 424 ten centavo coins.

Edwin</pre>