PT16.S2.Q9 - From 1973 to 1989 total energy use in this

jeeyoon.private

Hi,

I am looking for some help with percentage/numbers questions in general.
Most of the times I do get the answers right. But usually I hesitate between 2 of the answer choices and in blind reviews I tend to struggle explaining to myself why the correct answer is correct.

With this particular question, PT16, S2, Q9, I was down to (B) and (C). In the end I chose (C) because it "seemed more correct" given that the increase of electrical energy usage was larger (50%) than overall energy usage (10%). I also thought it is difficult to say anything about "other" energy types like in (B) as the stimulus does not give enough information about them.

As you can see, I didn't exactly have a confident reason in eliminating (B) and choosing (C). When I searched online for some explanations, they all came up with hypothetical numbers to show why (B) is not necessarily the case and (C) is. But I don't think I can come up with something like that during the exam under time constraint. So..

Can any of you tell me how you could go about during the actual exam environment in answering this question? Eliminating (B) with certainty and choosing (C)?

Thank you so much in advance!

Admin note: edited title

Clemens_

MBT // Proportions and Absolutes

1973
TOTAL ENERGY USE: X
ELECTRICAL ENERGY USE: Y
GNP: Z

1989:
TOTAL ENERGY USE: Between X and X x 1.10
ELECTRICAL ENERGY USE: More than Y x 1.50
GNP: More than Z x 1.50

MBT: From 1973 to 1989, the use of electrical energy increased by a greater percentage than the use of total energy during the same time period. This means: In 1989, electrical energy use must make up a larger proportion of all energy used than in 1973. This is exactly what (C) states. The point about the GNP is a distraction.

(A) We don't know anything about the distribution of energy use within the year 1989; we just know the development of different types of energy use over time.
(B) A decline in the use of other energy types is not necessary. We don't know anything about the % of the total energy use that electrical energy makes up.
(D) No. In 1989, electrical energy made up a larger percentage of the overall energy used than in 1973, but this does not have to mean that electricity was also the electricity form most consumed.
(E) Same as with (D); these last two answer choices get at the GNP distraction.

u______u

As Clemens_ noted above, this is a proportion vs. absolute, and it shows up from time to time. Without doing any number crunching try to understand it this way: the overall increased. A subset we don't have any idea what proportion of the overall it comprised increased. It could be that the subset made up a big proportion of the overall and its increase is what is predominantly driving the overall increase. But it could also be the case that the subset is so insignificant that even a 100% increase would drive the overall to only a 0.000005% increase. Without any indication of how much weight everything else that makes up the overall is contributing, the only thing you can really say about the proportion of the overall that the subset comprised increased.

Edit: I didn't realize this was from a 5 year old post...