Question

You and your brother each sell lemonade. You spend $35 on supplies and plan to charge $1.50$ per cup. Your brother spends $20 on supplies and plans to charge $1 per cup. How many cups of lemonade will each of you have to sell to earn the same amount of money?

Answer 1

P=R-C where R-revenue, C-cost
P=1.5c-35
P=c-20
c=cup
3/2c-35=c-20
3/2c=c+15
1/2c=15
c=30 cups
P=3/2(30)-35=45-35=$10
P=30-20=$10
so $30 to be even