Jada has a stand in the marketplace whare she sells cumin. her weekly expenses are $300, and she sells her cumin at a fixed price per kilogram. if she sells 120 kilograms of cumin, her weekly net profit is $600. what is the price of a kilogram of cumin? how much cumin does jada have to sell to cover her weekly expenses?

The net profit of the marketplace is the difference between the revenue and the expenses. The revenue is the product of number of kilograms sold and the price per kilogram. 
                            Profit  = Revenue - Expenses
                            600 = 120x - 300
The value of x from the equation is 7.5. The answer therefore for the first question is $7.5. Then, the number of kilogram of cumin she needs to sell to cover the expenses is $300/$7.5 and that is equal to 40.