How do i do it?can someone help

Apackage of bacon holds 15 strips of bacon. the pancake house uses 17 packages of bacon in the morning and 21 packages in the afternoon. how many more strips were used in the afternoon than the morning?

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%.

Gretchen is setting up for a banquet. she has 300 chairs and needs to distribute them evenly among t tables. how many chairs should she put at each table? write your answer as an expression.