Question 1154071
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Let x = # of the 20-dollar bills Philip has.


Then the number of 50-dollar bills is 2x, and the number of the 100-dollar bills is 2*(2x) = 4x.


Then the total money is  20x + 50*(2x) + 100*(4x) = (20+100+400)x = 520x dollars,

and it is equal to 1560 dollars, according to the condition.


    520x = 1560

   
Hence, x = 1560/520 = 3.


Thus, there are 3 20-dollar bills,  6 50-dollar bills and 12 100-dollar bills.


In all, there are 3+6+12 = 21 bills.      <U>ANSWER</U>.  
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Solved.