A company sells bulk landscaping materials. The table shows the price per cubic yard and the weight per cubic yard for four materials:
| Material | Weight per volume (lb/yd³) | Price per cubic yard ($) |
|---|---|---|
| Mulch | 400 | 35 |
| Topsoil | 2000 | 40 |
The equation gives the total cost, in dollars, for a delivery including cubic yards of mulch and cubic yards of gravel. If the delivery also includes topsoil and sand, and all four materials are present, which of the following is the best interpretation of the value in this equation?
The total weight of the topsoil and sand delivered.
The total cost of the mulch and gravel delivered.
The total cost of the topsoil and sand delivered.
The total volume of all materials delivered.
