There will be $100/$50 = <<100/50=2>>2 pieces of $50 when $100 is changed to $50 bills.
Half of $100 is $100/2 = $<<100/2=50>>50.
So there will be $50/$10 = <<50/10=5>>5 pieces of $10 when $50 is changed to $10 bills.
The remaining $50 will be changed to $5 bills so there will be $50/$5 = <<50/5=10>>10 pieces of $5 bills.
So in total, Lorie will have 2 $50 bills + 5 $10 bills + 10 $5 bills = <<2+5+10=17>>17 pieces of bills.
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