Self-study
Auditor: XYZ, a construction company, purchased 20 new trucks 3 years ago, and Support there is no record of any of those trucks being sold last year. ███████ █████████ ████████ ████ ███ ████ ███ ███ ██ ███ ██████████████ ██████ ████ █████ ██ ███ ████ ████████ ████ ████ ██ ███ ██ ██████ █████████ █ █████ ███ ████ ██████ ████████
Summary
The author concludes that none of the 20 new trucks that XYZ purchased 3 years ago were diesel powered.
What makes the author think this?
Because XYZ sold off all of its diesel-powered trucks last year. And there’s no record of any of the 20 trucks purchased 3 years ago being sold last year.
Notable Assumptions
The author assumes that none of the 20 new trucks purchased three years ago were sold before last year. (This overlooks the possibility that some of those trucks could have been diesel trucks that were sold two years ago. In that case, even though none of the 20 trucks were sold last year, some of them were still diesel trucks sold in a different year.)
19.
Which one of the following ██ ██ ██████████ ████████ ██ ███ █████████ ██████████
a
All of the ██████ ████ ███ ████ ████ ████ ████ ██████ ████████
Not necessary, because even if some of the trucks sold last year were diesel powered, we know that none of the 20 trucks purchased 3 years ago were sold last year. So whatever’s true about the trucks sold last year doesn’t affect the 20 trucks purchased 3 years ago.
b
XYZ did not ████████ ███ ████ ██████ █ █████ ████
Not necessary, because the argument concerns the 20 new trucks purchased 3 years ago. Even if there were some used trucks purchased, those aren’t the trucks the argument is about.
c
XYZ did not ████████ ███ ███ ██████ █████ ██ █████████ ███ ██ ██████ █ █████ ████
Not necessary, because even if XYZ did purchase new trucks after the 20 new ones it bought 3 years ago, those aren’t the trucks the argument is about. The argument concerns the 20 new trucks bought 3 years ago.
d
None of the ██ ██████ ███ ████ ██████ ████ █████
Necessary, because if it were not true — if SOME of the 20 trucks were sold before last year — then the fact that none of the 20 trucks were sold last year would not prove that none of them were diesel. The negation of (D) opens the possibility that some of the 20 new trucks purchased 3 years ago could have been diesel trucks, but were sold some time before last year.
e
XYZ no longer ████ ███ ██████ ████ ██ █████████ ████ ████ █ █████ ████
Not necessary, because the argument concerns the 20 new trucks purchased 3 years ago. What is true about other trucks purchased a longer time ago doesn’t affect the 20 new trucks purchased 3 years ago.