Total revenue is defined as the product of quantity of an item sold and it price. The price of an item is given by:

The total cost incurred is the sum of the fixed costs and operating costs. The latter increases as more items of a product are manufactured hence the total cost is given by:

For a given product, it is found that the number of item s sold corresponding to maximum profit is 25. Calculate the number of items sold corresponding to the break even point.