The circle with center (1,5) and radius 4 has equation

Adepartment store purchases screen-printed t-shirts at a cost of $5 per shirt. they mark up the price 150% (making the selling price 250% of the store's purchase price) and put them on the sales floor. every month that a t-shirt doesn't sell, the store reduces the selling price by 25%.

On a piece of paper graph f(x)=5•(0.4)^x

How much dextrose 70% must be mixed with dextrose 5% to prepare 1,000 ml of dextrose 20%?