Need help on number 3! Ik the answer for number 4 only 3!!!

Marcus built a model car that is 4 inches wide. what scale was used to build the car if the actual width of the car is 6 feet? a. 1 in. = 2 ftb. 1 in. = 2.5 ftc. 1 in. = 1.5 ftd. 1 ft = 1.5 in.

The expression 6x2 gives the surface area of a cube, and the expression x3 gives the volume of a cube, where x is the length of one side of the cube. find the surface area and the volume of a cube with a side length of 6m

Determine whether the set of whole numbers is closed under addition. explain why the set is or is not closed. give an example.