Which expression can be used to determine how much money Mary has left?

To find how much money Mary has left, subtract her total spending from the $20 she started with. Her spending is $5.50 + $3.75 + 2($1.25) + $2.75, where 2($1.25) accounts for two items costing $1.25 each. So the expression is $20 - (5.50 + 3.75 + 2(1.25) + 2.75), choice B.

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