Sales representatives Jones is based in Utah, where the operating plants and corporate headquarters of her employer also are located. She visits customers in Colorado for a day, soliciting, orders for the seashells that she sells. The orders are approved in Utah, and the shells are shipped from Oregon within a week. Are these sales subject to the Colorado corporate income tax?

This sounds like a homework assignment, which I will NOT answer as it defeats the purpose of the homework, which is to apply what you learned.