A factory which expects to operate 7,000 hours, i.e., at 70% level of activity, furnishes details of expenses as under:

Variable expenses Rs. 1,260

Semi-variable expenses Rs. 1,200

Fixed expenses Rs. 1,800

The semi-variable expenses go up by 10% between 85% and 95% activity and by 20% above 95% activity.

Construct a flexible budget for 80, 90 and 100 per cent activities.