He has a balance of $50.00 and is charged 20% interest so that's 50*.20 = $<<50*.20=10.00>>10.00
He had a balance of $50.00 and now has a $10.00 interest fee making his balance 50+10 = $<<50+10=60.00>>60.00
His balance is $60.00 and he puts another $20.00 on his card for a total of 60+20 = $<<60+20=80.00>>80.00
He didn't make a payment that month and is hit with another 20% interest fee so that's 80*.20 = $<<80*.20=16.00>>16.00 in interest
His new balance is 80+16 = $<<80+16=96.00>>96.00
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