To solve for the target sand in a mixture, which equation should be set up?

In this scenario, the goal is to determine the quantity of target sand in a mixture when taking into account the sand that starts in the mixture and how much is added or removed. The equation involves establishing a relationship between what is initially present and any changes that occur.

The correct choice emphasizes that the quantity of target sand can be derived by considering the starting amount of sand and accounting for any changes to that initial quantity. By adding the net sand change (which represents any additions or removals of sand) to the starting amount, you arrive at the total amount of target sand.

This setup allows for an accurate calculation by clearly distinguishing between what you begin with (starting sand) and any alterations (net sand change). It sets the foundation for understanding how mixtures work in terms of input and output, vital in situations where you manipulate quantities to reach specific desired outcomes.