What type of problem-solving requires solutions that are more than simply making decisions and choosing mathematical operations?

What type of problem solving that has an immediate solution?

During pandemic, Katheryn, and Myrna both donated money to the same charity. Katheryn gave three times as much as Myrna. They donated a total of Php 440 000. How much money did Myrna give?

Janet spent Php 100 on notebooks. This was Php 10 less than five times what she spent on ballpen. How much did she spend on ballpen?

If the perimeter of a rectangle is 22 inches, and one side is one inch longer than the other, how long are the sides?