The entry tickets for a local fair cost $7 for adults and $4 for children. In order for the fairgrounds to earn a profit, they must make at least $400. If this situation is modeled by the inequality7x +4y ≥ 400, which of the following constraints should be used to determine viable solutions?
• There is only one viable solution.
• A viable solution can include fractional values.
• A viable solution will have only positive whole numbers.
• A viable solution can have positive or negative numbers.