Throughout Region R, temperatures are such that households with air

Question

Throughout Region R, temperatures are such that households with air conditioning (AC) run AC only during Season X, which occurs every year. In one such household, AC always accounts for about half of all electricity consumption on days when AC runs for twelve hours. The table shows the household's electricity consumption in kilowatt-hours (kWh) for some months of 2022.

Month  
  Electricity Consumption (kWh)  
 
  January 
 620 
 
  February 
 624 
 
  March 
 704 
 
  May 
 1272

What was the household's approximate electricity consumption in April 2022?

(1) ﻿﻿﻿﻿In the household, AC ran for twelve hours every day during Season X of 2022. 
(2) ﻿﻿﻿Average daily temperatures in Region R remained about the same for three months from the start of Season X in late March of 2022.

https://gmatclub.com/forum/download/file.php?id=86830

Rohanx9 · Accepted Answer

I am struggling to accept the official answer (C). I selected (E) and here is my reasoning.

I understand that if we combine the statements, we know April is in "Season X" (Statement 2) and AC runs 12 hours (Statement 1). If we look at May (1,272 kWh) and apply the prompt's rule (AC is half the total on 12hr days), the implied "Base Load" for May is 636 kWh. Since Jan (620) and Feb (624) are similar, the solution assumes April's base load is also ~630, leading to a total of ~1,260 kWh.

My Objection (Why I chose E):  My issue is the assumption that Base Consumption implies stability across seasons. There is no stimulus in the prompt stating that non-AC electricity consumption is constant throughout the year.

It is entirely possible that Jan/Feb base load is 620 due to factors like heating or lighting (short days), whereas April's base load could drop significantly (e.g., to 400 kWh) before rising again in May.
Without a statement confirming "Non-AC consumption remains constant," how can we approximate April? Is the correlation between Jan, Feb, and the derived May base load enough to legally force the assumption of linearity for April?

Rohanx9 · Answer

Official Q Mock 3 https://gmatclub.com/forum/download/file.php?id=86830 GMAT-Club-Forum-xs8d6o7g.png

Bunuel · Answer

So I guess the logic is this. When we combine the statements, we know that Season X starts in late March, so May is fully in Season X. In May the total was 1,272, so about 600 kWh came from AC. Since the temperature stayed about the same for three months of Season X, we can assume the AC part in April was also about 600. And because AC accounts for about half of the total on those days, April’s total would be about 1,200.

js1986 · Answer

Can DS Questions ask "Approximately"? Doesnt that become subjective as to how much approximation is allowed? I dont think ive ever seen a DS Question from an official source before this which asks "Approximately". Would love if you could throw some light on this

Bunuel · Answer

It’s a GMAT Prep question, so the answer to your question is yes.

https://gmatclub.com/forum/download/file.php?id=86830

js1986 · Answer

Fair enough

but have you seen an Official DS Question using approximately before this?

Bunuel · Answer

I don't believe I have.

Alick1 · Answer

But I think, 
April and May are in the same constant-temperature period starting from Season X,

and we have May’s total,

we don’t need to know the 12-hour AC detail from (1) to figure out April’s approximate kWh.

So the correct Data Sufficiency answer is:

Statement (2) alone is sufficient, but Statement (1) alone is not.

Bunuel · Answer

(2) alone only gives “same temperature,” but it never says the AC was running twelve hours. Without that, you cannot apply the rule that  AC is about half of total when it runs twelve hours . Temperature by itself doesn’t translate into kWh.

Statement (1) supplies the missing twelve-hour condition, so only both together work.

ipsameos · Answer

Here it says that AC runs only during Season X: It is not necessary that AC runs for all months in Season X, right? Also, if it were true, and we take the same amount of KWH for AC from May to April, would that not be similar for March?

Bunuel · Answer

“AC runs only during Season X” just means no AC outside Season X. It does not guarantee AC runs every day in Season X. Statement (1) is the one that forces AC to run every day  during Season X .

As for March: Season X starts in late March, so most of March is still outside Season X with zero AC. That is why you cannot treat March like April and May. Only April and May are fully inside Season X with the same daily conditions.

ipsameos · Answer

Thank you, Bunuel!

Throughout Region R, temperatures are such that households with air

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Month	Electricity Consumption (kWh)
January	620
February	624
March	704
May	1272

GMAT Data Sufficiency (DS) Questions

Throughout Region R, temperatures are such that households with air

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