Labor Cost Considerations- please kindly answer questions in bold with given information.

The Alibi Restaurant is normally open for business until 8:00 p.m. Recently, business has been getting better during the time period just before closing, and the manager is attempting to determine the viability of remaining open until 9:00 p.m. She estimates her additional costs for the extra hour as follows:

Labor- $75

Heat, light, and gas- $12

Variable cost of food, beverage, etc.- 40% of sales

a. What additional sales are necessary for the manager to break even exactly on the extra hour of opening:

b. If the manager were able to obtain $280 in sales volume for the extra hour, what income could be applied to normal overhead expenses?

A restaurant's income statement shows the following cost and sales structure:

Sales: $450,000

Fixed costs: $135,000

Directly variable costs: $120,000

What must the semivariable cost figure be if the restaurant is to show a profit of $30,000?