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 on a cart and the cart is being pushed to the right. The scale is wedged in between the vertical wall of the cart and the box. The only object under the box is the bed of the cart. We do not know a lot about the horizontal motion - whether it is constant speed or accelerated - but we do know that there is no vertical motion since the surface is level. 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. Your analysis will have to include some attention to direction of forces.
There are two obvious contact forces on the box - the normal force (rightwards) from the scale and the normal force pushing (upwards) from the bed of the cart. And then there is the force of gravity (the Earth pulling the box downard). When analyzing the vertical forces, one must conclude that they are balanced since the box is at rest. So the normal force from the cart (directed upwards) is balanced by the downward force of gravity. But the horizontal motion is independent of these vertical forces. And so there is no way to compare the rightward force of the scale to the downward force of gravity.