Last year the amounts of electric company supplied to 4,117 residentia

Question

https://gmatclub.com/forum/download/file.php?id=74300 Last year the amounts of electric company supplied to 4,117 residential properties and 2,504 commercial properties were recorded to the nearest thousand kilowatt-hours and summarized in the graph shown. The median of the amounts of electricity recorded is in which of the following categories? (A) 5-9 (B) 10-14 (C) 15-19 (D) 20-24 (E) 25-29 1.png

youcouldsailaway · Accepted Answer

In order to find the median, we need to first calculate the sum of all the properties. You can find the total by adding 4117 and 2504, or you can add the value on top of each bar in the histogram to find the total; you'll get the same answer, which is 6621.

Now to find the median, we need to do the following calculation: (6621 + 1) /2  .

Thus, the median property is the 3311st property.

Now, looking at the histogram, we see 1370 properties lie in the class of 0-4 and 1995 properties lie in the next class of 5-9. If we only consider 0-4, we will not reach the median property and thus we have to move to the next class.

If we add 1370+1995, we get 3365. That is, these two classes combined, have 3365 properties and the class of 5-9 includes the median property 3311.

Thus answer is A.

Kinshook · Answer

DALC1 
 https://gmatclub.com/forum/download/file.php?id=74300

Given: Last year the amounts of electric company supplied to 4,117 residential properties and 2,504 commercial properties were recorded to the nearest thousand kilowatt-hours and summarized in the graph shown. 
Asked: The median of the amounts of electricity recorded is in which of the following categories?

1370+1995+956+205+396+1248+451=6621
For median ,we have to check where 6621/2 = 3310.5 lies

1370 + 1995 = 3365
Median lies in 5-9 category.

IMO A

aidenazaar · Answer

Shouldn’t the question mention median property rather than median amounts of electricity? The wording, that too from an official question seems confusing to me here.

Posted from my mobile device

Bunuel · Answer

This is an official question from GMAT Prep Focus.

ManifestDreamMBA · Answer

Median range = ?
Total properties = 4,117 + 2,504 = 6,621

The median for these will be 3311th property

Finding the cumulative sum to see where this lies
 0-4:  1370
 5-9:  1370+1995 = 3365, it lies in 5-9

Bunuel · Answer

https://gmatclub.com/forum/download/file.php?id=74300

Last year the amounts of electric company supplied to 4,117 residential properties and 2,504 commercial properties were recorded to the nearest thousand kilowatt-hours and summarized in the graph shown. The median of the amounts of electricity recorded is in which of the following categories?

(A) 5-9
(B) 10-14
(C) 15-19
(D) 20-24
(E) 25-29

Show Spoiler

Attachment:

1.png

(A) 5-9
(B) 10-14
(C) 15-19
(D) 20-24
(E) 25-29

The graph shows the distribution of 4,117 + 2,504 = 6,621 properties by the electricity ranges they received. For instance, 1,370 properties fall into the 0-4 range, so they received between 0 and 4 thousand kilowatt-hours; 1,995 properties fall into the 5-9 range, so they received between 5 and 9 thousand kilowatt-hours; and so on.

The median amount of electricity for the 6,621 properties is the amount received by the 3,311th property when the amounts are ordered from least to greatest.

The first 1,370  amounts  are in the 0-4 range.

Adding the next 1,995  amounts  from the 5-9 range brings the cumulative total to 3,365  amounts .

So, the median value, the amount received by the 3,311th property, falls into the 5-9 category.

Answer: A.

We are asked about the median of the  amounts  of electricity. The median  amount  is the 3,311th value, not the median group. The question asks in which category this  amount  falls. For example, we have 1,370 properties with  amounts  between 0 and 4 thousand kilowatt-hours (For example: 2, 2, 2, .... 1,370 times), and 1,995 properties with  amounts  between 5 and 9 thousand kilowatt-hours (for example: 6, 6, 6, ... 1,995 times), and so on. The 3,311th  amount  falls into the 5-9 range.

ribbons · Answer

Thanks, what would the question ask if it wanted to know the median of 7 amounts ?

Bunuel · Answer

Which seven amounts are you referring to exactly? For this question, that does not make sense.

Last year the amounts of electric company supplied to 4,117 residentia

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

Last year the amounts of electric company supplied to 4,117 residentia

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards