Mark drinks one cup of coffee everyday. He orders a coffee from Dunkin Donuts and it costs him $3.50 everyday. He is starting to think that he might buy a Keurig and k-cups instead. The Keurig is $150 and each k-cup costs $0.50. How many cups of coffee will it take for the cost at Dunkin Donuts to be the same as having a Keurig and k-cups?