Do number 13 and answer all question

Volume of a cylinder with a radius of 13 in and height of 30 in

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%.

Simplify this expression. 8x 16(x + y)