Lesson 5 hw, Game 12, Question 11

[Blueballoon5%]

The answer key explains that the options are: (1) Large Yellow or Small Yellow, (2) Medium Red, (3) Medium Blue

But why is Medium Yellow not an option? The conditions do not indicate that we cannot have two of the same color.

Moreover, it seems like answer C is the right answer. It must be true that Casey can buy either a large shirt or a small shirt (but not both).

[David Boyle]

The answer key explains that the options are: (1) Large Yellow or Small Yellow, (2) Medium Red, (3) Medium Blue

But why is Medium Yellow not an option? The conditions do not indicate that we cannot have two of the same color.

Moreover, it seems like answer C is the right answer. It must be true that Casey can buy either a large shirt or a small shirt (but not both).

Hello Blueballoon5%:

Medium yellow is an option, actually. That does not mean that answer B is correct.
Answer C is wrong, since Casey could buy three medium shirts instead. "It must be true that Casey can buy either a large shirt or a small shirt" is true since you said "can", not "must". And answer D makes sense, since if you take away two medium shirts, then Casey must buy a small, medium and large shirt, which is forbidden.

Hope this helps,
David