Question: I'm completely lost with this math problem: To raise money for their class fund, each of the 30 students from one class sold lollipops that cost $0.8 per lollypop. On average, each student sold 10 lollipops. If they bought the lollipops for $0.5 each, how much money was the class able to raise from the profit of selling lollipops?
Can you give me a hand?
Answer: 
The class got $0.8 - $0.5 = $0.3 profit from each lollipop.
So each student raised $0.3 x 10 = $3 from selling 10 lollipops.
Therefore, they were able to raise a total of $3 x 30 = $90.