When a price of a scientific equipment increased 400 birr, a company sold 20 every

month, where as price dropped to 200 birr, 120 where sold every month. When the price

of 400 birr, 200 scientific equipments were available per month for sale where as the

price rigid at 100 birr only 50 remained. Find the demand and supply functions assuming

both linear. Find producer and consumer surplus and interpret it.