Self-paced
The only way that bookstores can profitably sell books at below-market prices is to get the books at a discount from publishers. ██████ ██████████ ████████ █ ████ █████ ███████ ████████ ████ ██████ ███ █████████ ████ ███████████ ██ ████████ ████ ███████ ██████████ ████ ██████ █████ ██ ████ ██████ ██ ████ █████████ ██████ ██ █ █████ ███████████ ███████ ████ ██ ███████ ██████████ ██ █████
Use Formal Logic
If thinking about this question in English was challenging, consider more practice to gain fluency in formal logic. Here’s the argument presented in both languages:
English
- If a bookstore is profitably selling below-market books, they have a discount from publishers.*
- If they have a discount, they’re selling at high volume.**
- If they’re selling at high volume, they either cater to the masses or have exclusive access.
Logic
- Profits → Discount*
- Discount → Volume**
- Volume → Cater or Exclusive
*The only is a sufficient condition indicator.
**We’re diagramming unless here in the form that’s most convenient for the argument’s flow.
These claims form a big ol’ conditional chain, which is nice to view in both directions:
Default: Profits → Discount → Volume → Cater or Exclusive
Contrapositive: /Exclusive and /Cater → /Volume → /Discount → /Profits
13.
Which one of the following ███ ██ ████████ ████████ ████ ███ ████████
a
If a bookstore ████████ █████████ ████ ███████████ ██ ████ ██████████ ████ █████ ██ ████████████ ███████
This reverses the first claim.
b
A bookstore that ██████ ██ ████ ██████ ██ ███ █████████ ██████ ██ █ █████ ███████████ ██████ ████ ████ █ ████ █████ ███████
This reverses the third claim.
c
A bookstore that ██████████ █████ █████ ██ ████████████ ██████ ████ █████████ ████ ███████████
This restates the first claim.
d
A bookstore that ████ ███ ████ █████ ██ ████████████ ██████ ████ ███ ███ █████████ ████ ███████████
This inverts the first claim.
e
A bookstore that ███ ████ ██████ ██ ████ ██████ ███ ████ ███ █████████ ██████ ██ █ █████ ███████████ ██████ ██████ ██████████ ████ █████ ██ ████████████ ███████
This attempts to go from "Cater and Exclusive" to "/Profit", which is kinda like the contrapositive if you forget to negate the terms "Cater" and "Exclusive".
Note their intentionally deceptive use of the word "not" here, where "not only" basically just means "this and also that".