Definite integrals with substitution. Please help if you know how to do it.

Ablock of wood is a cube whose side is x in. long. you cut off a 1-inch thick piece from the entire right side. then you cut off a 3-inch thick piece from the entire top of the remaining shape. the volume of the remaining block is 2,002 in3. what are the dimensions of the original block of wood?

Ahiking trail is 6 miles long. it has 4 exercise stations, spaced evenly along the trail. what is the distance between each exercise station?

Can someone check if i did this correct. it’s number 4 if you’re wondering.