Maintenance cost for Ricwy corporation is given by following equation y = $4800 + $0.40x, where x is machine hours As mentioned in the problem statement, 9000 machine hours are planned in august. Therefore, maintenance cost for this month can be calculated as, Cost (y) = $4800 + $0.40 X 9000 => y = $4800 + $3600 => y = $8400 So, the cost for august month is $8400