#14 - Among a sample of diverse coins from an unfamiliar

[Administrator]

Complete Question Explanation

Must Be True-SN. The correct answer course is (D).

This stimulus provides four design possibilities (judge’s head, explorer’s head, building, tree) and the following conditional statements:

• head on one side → head on the other side

• judge’s head on one side → tree on the other side.

• Contrapositive: tree on one side → judge’s head on the other

Correct answer choice (D) reflects the contrapositive statement above. None of the other answer choices are supported by the conditional statements provided in the stimulus.

[akatormubarez]

I am confused as to how the answer choice is D. There is no explanation for the wrong answers. I got A because if j -->t and contrapositive is if not t --> not j and if e --> b and contrapositive for that is if not b --> not e. Please explain. Thanks!

[Steve Stein]

Hi akatormubarez,

The author provides that all of the coins with a judge's head on one side had a tree on the other:

judge's head tree

As you correctly diagrammed, if there is no tree there is no judge's head

tree judge's head

The contrapositive diagram above confirms answer choice D: if there is a building on one side of the coin, that's not a tree, so it would be impossible to find a judge's head on the other side.

Answer choice A is incorrect because an explorer's head on one side of a coin still leaves open the possibility that the other side of the coin will display a tree.

I hope this is helpful! Please let me know whether this is clear--thanks!

~Steve

[akatormubarez]

It was, thank you!

[Nadia0702]

Hi Steve, as a follow-up question, can you please diagram all of the answer choices? I had trouble with this question and diagrammed all of the answer choices and want to make sure they are diagrammed correctly. Thanks!

[Steve Stein]

Hi Nadia,

I think it would be more helpful if you would provide the diagrams that you created, and we can assess them for you.

Thanks! I look forward to your response.

~Steve

[Nadia0702]

Hi Steve,
Sure. Here they are: (underline means not)

A) Explorer's head on one side --> Building on other side
B) Tree on one side --> Judge's head on other side (MR)
C) Tree on one side --> Explorer's head on other side
D) Building on one side --> Judge's head on other side (Building is not a tree, thus correct answer)
E) Explorer's head on one side -->Building on other side

I occasionally have trouble with "None" at the start of a sentence, and thus wanting to double check C-E mainly. "None" as in "no" modifies the necessary condition, right?

Thank you for your help!
Nadia

[Steve Stein]

Hey Nadia,

Thanks for your response--looks like you've got it! All of your diagrams look good--nice work!

~Steve

[Nadia0702]

Great, thanks for your help, Steve!

[rameday]

Hello,

So I understand why this stimulus was clearly conditional because of the absolute language (none and all) however how did you know which was the sufficient condition and the nec. condition for the sentence "none of them have heads on both sides)? Is none a sufficient indicator word?

Fortunately I remembered that any was a sufficient indicator word soI was able to diagram the second diagram but I totally missed out on the first one.

A