Question 17154
To solve this you need  "quantity" information  and  "value" information.
Quantity Information is as follows:
Let "x" be the number of ten-dollar bills.
Then "x+10" is the number of five-dollar bills.
And 91-(x+x+10)= [91-2x-10]=[81-2x] one-dollar bills.
Value information:
Value of the ten-dollar bills is 10x
Value of the 5=dollar bills is 5(x+10)=5x+50
Value of the 1-dollar bills is 1[81-2x]
Equation:
   Value of 10-dollar + Value of 5-dollar + Value of 1-dollar = 547 dollars
            10x + 5x+50 + 81-2x = 547
                        13x +81 = 547
                        13x     = 466
                          x     = 35.85 (number of 10-dollar bills)
That doesn't make any sense.  I suspect you did not post the information
stated in your problem regarding regarding how the number of one-dollar
bills relates to the number of ten-dollar bills.  Check your problem 
statement.

Cheers,
Stan H.