At a discount store, items are discounted by the same amount each week. the graph shows the relationship between time and cost of an item with an original cost of $300. at what rate is the item discounted each week?

Starting at home, emily traveled uphill to the hardware store for 606060 minutes at just 666 mph. she then traveled back home along the same path downhill at a speed of 121212 mph. what is her average speed for the entire trip from home to the hardware store and back?