Eight less than double a number is ten. What is the number?

You dug a hole that was 8 feet deep. after taking a short break, you dug down 3 more feet in the same hole. when finished digging, a tractor accidentally filled the hole with 4 feet of dirt. how deep is your hole now?

An elevator travels 310 feet in 10 seconds. at that speed, how far can't his elevator travel in 12 seconds?

Find the volume of the wedge cut from the first octant by the cylinder z=12-3y^2 and the plane x+y=2.