The following data relate to activity and costs for two recent months:

November

December

Activity level in units

5,000

10,000

£

£

Variable costs

10,000

?

Fixed costs

30,000

?

Semi-variable costs

20,000

?

Total costs

60,000

75,000

Assuming that both activity levels are within the relevant range, calculate for December the:

  • variable costs;
  • fixed costs;
  • semi-variable costs.