【单选题】Alyssa rents 5 movies per month when the price is $3.00 per rental and 7 movies per month when the price is $2.50 per rental. Alyssa’s demand demonstrates the law of
【单选题】Bob plans to spend $60 per month on DVD movie rentals and CDs. The price of a movie rental is $3 and the price of a CD is $15. If Bob rents 5 DVDs per month, how many CDs can he buy?