Mandy has a total of $20 x 3 = $<<20*3=60>>60.
So, she will have $60/$10 = <<60/10=6>>6 $10 bills.
Manny has a total of $50 x 2 = $<<50*2=100>>100.
So, he will have $100/$10 = <<100/10=10>>10 $10 bills.
Hence, Manny has 10 - 6 = <<10-6=4>>4 more $10 bills than Mandy.
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