A box contains 27 cubic feet of sand weighing 105 lbs per cubic foot. What is the equation to find the total weight of the filled box if it weighs 1200 lbs when empty?

To find the total weight of the filled box, it's necessary to consider both the weight of the sand and the weight of the empty box.

The weight of the sand can be calculated by multiplying the volume of the sand (27 cubic feet) by its weight per cubic foot (105 lbs). This gives a total weight for the sand of 27 multiplied by 105.

Once this total weight of the sand has been established, the final step is to add the weight of the empty box, which is 1200 lbs. Thus, the equation combines these two components: the total weight of the sand plus the weight of the empty box.

This results in the correct expression being 27 multiplied by 105, added to 1200. This accurately represents the total weight of the box when filled with sand.