The more difficult questions in this Concept Builder include a variety of distracting elements. The trick is to use the same type of analytical and principled-thinking that you used on the easier questions.
Here the 5.0-kg box is at rest on top of the scale. But there is a second box on top of it. You want to know how the scale reading - that is, the normal force acting between the box and the scale - compares to the weight of the 5.0-kg box. To do so, consider the forces acting upon the box (the box at rest on the scale).
There are two contact forces - the normal force (upwards) from the scale and the normal force pushing downwards from the top box. And then there is force of gravity (the Earth pulling the box downard). These three forces must balance each other since the box is at rest. So the one up force - the normal force from the scale - is equal to the two downward forces (one of them being the weight of the box). So from this type of analysis or reasoning, you should be able to determine the strength of the normal force relative to the weight of the box.
Another Way to Think About It
A first step in any force analysis involves the decision as to what the system is. One way to approach this question is to consider the system to be the set of two boxes. The idea is to pretend the boxes act together as one object. In such a case, you would reason that there are two forces on the system - the force of the scale pushing upward on this system of two boxes AND the downward force of gravity of the two boxes. This downward force is equivalent to the combined weight of both boxes. In such an analysis, the normal forces is equal to the weight of the bottom box plus the weight of the top box. This type of thinking allows you to conveniently compare the normal force to the weight of the 5.0-kg box.