Answer:
$162
Step-by-step explanation:
$1200 x .045 = $54 x 3 years = $162
True
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A closed circuit basically means everything is connected by wires and for this setup every device receives electricity making this true
For a you need to do (10 times 13) plus (10 times 7) because there's two boxes one is shaded.
For b you need to do (7.5 times 20) plus (2.5 times 20)