Vincen wrote: ↑

Tue Sep 08, 2020 7:35 am

If the list price of a new car was $12,300, what was the cost of the car to the dealer?

(1) The cost to the dealer was equal to 80 percent of the list price.
(2) The car was sold for $11,070, which was 12.5 percent more than the cost to the dealer.

Answer: D

Source: Official Guide

Given: The list price of a new car was $12,300

Let x = the cost of the car to the dealer

Target question: What is the value of x?

Statement 1: The cost to the dealer was equal to 80 percent of the list price.
Rewrite as: cost to the dealer = 80% of list price
Substitute to get: x = 80% of $12,300
Since we COULD evaluate 80% of $12,300, we COULD find the value of x, which means we could answer the target question with certainty (but we'd never waste our time doing so on that day!)
Statement 1 is SUFFICIENT

Statement 2: The car was sold for $11,070, which was 12.5 percent more than the cost to the dealer
We can write: $11,070 = 12.5% more than the cost to the dealer
In other words: $11,070 = 12.5% more than x
In other words: $11,070 = x + (12.5% of x)
In other words: $11,070 = x + (0.125x)
In other words: $11,070 = 0.125x
Solve: x = 11,070/0.125
Since we can answer the target question with certainty, statement 2 is SUFFICIENT

Answer: D

Cheers,
Brent