Babaganoush’s electricity supply company charges him a fixed quarterly sum plus a rate per unit for electricity used. In the most expensive quarter last year (January to March), he used 2,400 units and his bill was $320. In the least expensive quarter (July to September), he used 800 units and his bill was $144. He is now adding extra insulation to his home which is expected to reduce his overall electricity consumption by 25%.
What can he expect his January to March bill to be next year (if there are no increases in overall tariffs)?