Soylent Yellow is sold for the (relatively) low price of only $120 per bar. But the much tastier and more nutritous Soylent Green costs $245 per bar. A food merchant wants to create combination meal bars at a cost of $180 per bar. Each bar will have part of a Soylent Yellow bar, and part of a Soylent Green bar. The merchant already has 300 Soylent Green bars to use for his new product. He wants to know how many Soylent Yellow bars, y, he should buy to acheive the a mixture with the correct cost. Which equation below represents the situation?