Each barge operates 25 days per month. The monthly charge must be paid even if fewer than 100 tonnes are transported on any day and even if requires fewer than 25 days of barge transportation in that month. is currently mining tonnes of beach sands per day for 25 days per month.

1. What is the variable cost per tonne of beach sand mined? What is the fixed cost to per month?

2. Plot a graph of the variable costs and select the graph that shows the fixed costs of . Is the concept of relevant range applicable to your graphs?

Explain.

3. What is the unit cost per tonne of beach sand mined (a) if tonnes are mined each day and (b) if tonnes are mined each day? Explain the difference in the unit-cost figures.