Balzania put in place regulations

[JianchengD868]

cool.

just make sure that you read SLOWLY ENOUGH to absorb these sorts of things. 99.99999 per cent of all misunderstandings stem from rushing through the text, and/or from the stress caused by rushing).

Hi Ron,
Thank you for your help.
Best,
Jiancheng

[RonPurewal]

sure.

[JbhB682]

The use of coal as a fuel has gone down, therefore I inferred that coal production has gone down

This ^^ is a questionable inference to start with. It's certainly reasonable, but, depending on how fixed costs work, the opposite might be true, too. (E.g., now that fewer people are using first-class mail, the cost of a first-class stamp continues to increase, because the fixed costs of the postal system are spread over fewer delivery charges.)

That's not the main point, though.

The main point is that the statistic in the passage is explicitly chosen to make this consideration irrelevant:

and as a result, less lands need to be reclaimed.

By considering this cost in terms of dollars PER TON OF COAL, we are engineering the statistics to make the volume of mining irrelevant.
Looking at "per ___" statistics makes the size of "____" irrelevant.
Consider per-capita (= per population) crime statistics. Those make the actual population of a city irrelevant, enabling direct comparisons between the crime rates of cities of different sizes. (The number of crimes, by contrast, will normally be higher in bigger cities, even if those cities are safer than the smaller ones.)

Hi Ron ...

Just wondering, what are the factors that affect this per capita statistic you mentioned in red

For example - the crime statistics have increased by 50 % to 25 cases of crime / 1000 residents in this neighborhood

Just wondering if these are the factors affecting (not affecting) this statistic

-----------------------------

Quant Factors related to the statistic

Increase in total number of crimes committed in the country ..... i think this is a factor but not entirely sure ...my thinking is if total number of crimes committed are higher , the numerator when dividing by 1000 gets larger

Quant Factors not affecting this statistic

More total residents have entered the neighborhood

Just wondering if my understanding of statistics per unit is accurate ...

[Sage Pearce-Higgins]

I think you've misunderstood Ron's point here. He's saying that when we have a change in the rate, such as ___per____, then the change in the overall volume is not relevant. Clearly, however, to calculate the rate we need to consider both sides. If we're working out a rate such as crime per 1000 population, we need to add up the total crimes, add up the total 1000s of population, then divide to find the rate.

Well done for applying the same idea to another situation, but I don't understand your example because the phrase 'Quant factors related to the statistic' is vague. Try writing 3 correct and 3 incorrect answer choices for the following question: The crime rate in the city of Ronford has decreased from 50 crimes per 1000 population to 40 crimes per 1000 population over the last 2 years. What could help explain this decrease.

[JbhB682]

Hi Experts - I understand why C is right. Just wanted to focus on B specifically to see if my analysis on B is right or wrong ...

Lets say there are 3 surface coal mines
-- Surface mine 1 - 1$/ton of coal produced
-- Surface mine 2 - 7 $/ton of coal produced
-- Surface mine 3 - 22 $/ton of coal produced

Thus the average cost/ ton produced is 10 $/ 1 ton of coal produced

If you get rid of coal mine # 3, the average drops to 4 $ / ton of coal

Question 1) If surface mine # 1 suddenly doubled its coal production for whatever reason , it's individual ratio of 1 $/ton of coal produced now be <1 / ton of coal.

Per my understanding it will .. Is that accurate ?

Question 2) Option B say the use of coal "as a fuel" has dropped.

Does this mean, each surface mine's individual coal production will go down because of this ? My understanding is not necessarily.

Because perhaps coal produced by underground mines (not surface mines) will go down , keeping surface mine # 1, surface mine # 2, surface mine # 3 coal production exactly the same

This is the reason why I believe B does not affect the argument.

[esledge]

I'm unclear whether the $ amounts you gave for the three hypothetical mines are profit, reclamation costs, or something else... And none of those scenarios are suggested by choice (B), so my overall advice would be "don't overthink about choices that are not directly and explicitly tied to the conclusion in a known way." Just dismiss them and move on.

So to answer your questions:

Q1: Since "reclamation cost" is described in terms of "dollars per ton of coal that the mine produced," the reclamation cost could be halved if (a) the numerator (dollars) were cut in half, (b) the denominator (tons of coal produced) were doubled, or (c) some combination of an increase in the denominator and a decrease in the numerator. So, yes, your reasoning is correct....But nothing about choice (B) in particular addresses this.

Q2: (B) just states that "the use of coal as a fuel has declined," but you would have to make assumptions and speculate about what, if anything, that means for reclamation costs.

Question 2) Option B say the use of coal "as a fuel" has dropped.

Does this mean, each surface mine's individual coal production will go down because of this ? My understanding is not necessarily.

Exactly: "not necessarily" = irrelevant. Dismiss (B) here without further thought.

This is the reason why I believe B does not affect the argument.

Correct.

[JbhB682]

I'm unclear whether the $ amounts you gave for the three hypothetical mines are profit, reclamation costs, or something else... And none of those scenarios are suggested by choice (B), so my overall advice would be "don't overthink about choices that are not directly and explicitly tied to the conclusion in a known way." Just dismiss them and move on.

So to answer your questions:

Q1: Since "reclamation cost" is described in terms of "dollars per ton of coal that the mine produced," the reclamation cost could be halved if (a) the numerator (dollars) were cut in half,(b) the denominator (tons of coal produced) were doubled, or[/color] (c) some combination of an increase in the denominator and a decrease in the numerator. So, yes, your reasoning is correct....But nothing about choice (B) in particular addresses this.

Hi Emily - in the three scenario's I suggested for mine # 1, mine # 2 and mine # 3 -- it was each mine's individual reclamation cost per mine (reclamation cost being dollar per ton of coal that the mine produced)

for some reason, when I read option B, I immediately thought about the red would happen for each of the three mines.

In fact if anything, if overall coal usage goes down (which it did not necessarily), the denominators would DECREASE, thus the individual reclamation cost per mine would RISE), resulting in a HIGHER average reclamation cost

That would be the opposite of what the premise told us (the premise says, the average reclamation cost per mine decreased, not increased)

[esledge]

for some reason, when I read option B, I immediately thought about the red would happen for each of the three mines.

In fact if anything, if overall coal usage goes down (which it did not necessarily), the denominators would DECREASE, thus the individual reclamation cost per mine would RISE), resulting in a HIGHER average reclamation cost

That would be the opposite of what the premise told us (the premise says, the average reclamation cost per mine decreased, not increased)

Ahhh, maybe that's why I didn't see the connection between (B) and your examples! Yes, what you say immediately above is true. Your example mine #3 had the highest reclamation cost per ton produced, which would imply (all other things equal) that it had the lowest production. Thus, choice (B) would actually suggest that reclamation costs would approach the higher-cost mine #3 level, not lower-cost mine #1 or #2 levels.