Self-study
Support All etching tools are either pin-tipped or bladed. █████ ████ ██████ ███████ █████ ███ ████ ███ ██████████ ████ ███ ████ ██ ███ █████ █████ ███ ██████████ ███████ █████ ███ ████ ███ ██████████ █████ █████ ███ ████ ███████ █████ ████ ███ ████ ███ █████████ ████ █████ ███ ███████ █████ ████ ███ ███ ████ ███ ██████████
Summary
The author concludes that, for engraving, there are more engraving etching tools than non-engraving etching tools. Why? Because all etching tools are either pin-tipped or bladed; pin-tipped are always engraving tools, and bladed tools could be either.
Missing Connection
The conclusion is a comparative statement of quantity (actual numbers), but we don’t have information about quantity. If pin-tipped tools aren’t high enough in numbers, the conclusion won’t be true. We need to know either that pin-tipped and bladed are equal in number of tools, or that pin-tipped is larger in number.
Illustrating the argument’s weakness in a hypothetical: Maybe pin-tipped only accounts for two tools, while bladed accounts for 300 tools and 2/3rds are non-engraving.
16.
The conclusion of the argument ███████ █████████ ██ █████ ███ ██ ███ █████████ ██ ████████
a
All tools used ███ █████████ ███ ███████ █████ ██ █████
This does not solve the weakness described in our analysis. Without knowing the total quantity of the sets pin-tipped and bladed, we could still have a situation where non-engraving tools outnumber the engraving tools.
b
There are as ████ ██████████ ███████ █████ ██ █████ ███ ██████ ███████ ██████
If this is true, then there’s no possible distribution of bladed tools that could prevent our conclusion. Even if there’s only one bladed tool used for engraving, the combination of pin-tipped and bladed engraving tools will still outnumber non-engraving.
c
No etching tool ██ ████ ██████████ ███ ███████
We already knew this. Though not explicitly stated, we can safely interpret “All etching tools are either pin-tipped or bladed” to mean that they must be one or the other, but not both. It also does not guarantee our conclusion.
d
The majority of ██████ ███████ █████ ███ ███ ████ ███ ██████████
This does not guarantee that engraving tools outnumber non-engraving, or the other way around. We could manipulate the unknown total number of bladed or pin-tipped tools to suit either conclusion. We need to know that the total number in each set will prevent that from happening.
e
All etching tools ████ ███ ███ ████ ███ █████████ ███ ███████
We know this as inference from the support: All etching tools are either pin-tipped or bladed, and all of the non-engraving etching tools are in the bladed category.