Data for Hermann Corporation are shown below:

Per Unit Percent of Sales

Selling price $ $95100\%$

Variable expenses $5760$

Contribution margin $ $3840\%$

Fixed expenses are $$79,000$ per month and the company is selling $3,600$ units per month.

Exercise $6-7($Algo$)$ Part $1$

Required:

$1-$a$.$ How much will net operating income increase $($decrease$)$ per month if the monthly advertising budget increases by $$8,400,$ the monthly sales volume increases by $100$ units, and the total monthly sales increase by $$9,500?$

$1-$b$.$ Should the advertising budget be increased?