A hot dog stand sold 1/4 of their hot dogs for $20. They then added 5 more hot dogs and sold 4 of them. How much money did they make from the sale of the hot dogs?
Clearly, if they had sold them all, they'd have made $80
If they sold 1 dog for $20, then the extra 4 dogs would net them another $80, for total sales of $100
If they sold 2 dogs for $20, then the extra 4 dogs would net them another $40, for total sales of $60
end so on
But the data given are insufficient to determine the exact amount.