A 3-D figue is made with 11 cubes. The top view is 5 squares. What is the greatest number of cubes in a stack represented by one of the 5...

To begin with, you know that five squares can be seen when
a person looks down on the figure. Each stack must be at least one square tall.
Therefore, you can conclude that five of the eleven cubes must be on the lowest level of
the figure. No additional information is given about the heights of any of the five
stacks that make up the figure. The remaining six cubes could be spread out over the
five base cubes, or they could all be piled in one stack. The question asks for the
greatest number of cubes that could be in one stack, therefore, pile the six remaining
cubes on top of one of the base cubes. Six cubes plus the base cube equals seven
cubes.

The correct answer is d) 7.