=+Consolidated Minerals (CM) owns the rights to extract minerals from beach sands. CM has costs in three areas:

a payment to a mining subcontractor who charges $80 per tonne of beach sand mined and returned to the beach (after being processed on the mainland to extract three minerals: ilmenite, rutile and zircon)

b payment of a government mining and environmental tax of $50 per tonne of beach sand mined c payment to a barge operator. This operator charges $150000 per month to transport each batch of beach sand—up to 100 tonnes per batch per day—to the mainland and then return to Fraser Island (i.e. 0–100 tonnes per day = $150000 per month; 101–200 tonnes per day = $300000 per month, and so on).

Each barge operates 25 days per month. The $150000 monthly charge must be paid even if fewer than 100 tonnes are transported on any day and even if CM requires fewer than 25 days of barge transportation in that month.

CM is currently mining 180 tonnes of beach sands per day for 25 days per month.

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