Identify the cylinder with the smallest surface area

An advertising firm has an old computer that can prepare a whole mailing in 6 hours. with the of newer model the job is complete in 2 hours. how long would it take the newer model to do the job alone?

Asegment in the complex plane has a midpoint at 7 – 2i. if the segment has an endpoint at 11 – 3i, what is the other endpoint?

Three numbers x, y, and z are in the ratio 2: 7: 8. if 12 is subtracted from y, then three numbers form a geometric sequence (in the order x, y–12, z). find x, y, and z. there are 2 sets.