Students sold yogurt to raise money for graduation. The first 20 yogurts sold cost $5 each. To sell more yogurt they lowered the cost to $4 each. If they raised $216, how many yogurts did they sell in all?
5(20) + 4y = 216 100 + 4y = 216 4y = 216 - 100 4y = 116 y = 116/4 y = 29.....so they sold 29 four-dollar yogurts + 20 five-dollar yogurts....for a total of 49 yogurts sold <==
