Earnings from gas station=(30hrs)($8.75/hr)
Earnings from gas station=$262.50
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Amount as landscaper=Total to earn-earnings from gas station
Amount as landscaper=$400-$$262.50=$137.50
You need to earn $137.50 as a landscaper.
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Amount as landscaper=(hours)(pay per hour)
$137.50=(hours)($11/hour)
($137.50)/($11/hour)=(hours)
12.5 =hours
ANSWER: You must work 12.5 hours as a landscaper to total $400 per week.
hope it helps