The 200 quarters equals 200*$0.25 = $<<200*0.25=50>>50.
Oliver has a total of $40+$50 = $<<40+50=90>>90.
He gives his sister 120*$0.25 = $<<120*0.25=30>>30 in total from the quarters.
The total amount he gave to his sister is $30+$5= $<<30+5=35>>35.
Oliver is left with $90-$35 = $<<90-35=55>>55.
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