Question 1016199
Call the number of $10 and $20 bills, x and y.  Then we have
x + y = 17 and the value equation is
10x + 20y = 230  Now multiply the top one by ten and subtract and get
-(10x + 10y = 170)
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10y = 60
y = 6 $20 bills
and then we must have
x = 11 $10 bills