During the time periods in which City Y’s average daily temperature

Question

1.jpg During the time periods in which City Y’s average daily temperature was increasing while City X’s was decreasing, the average daily temperature in City Y exceeded that in City X by approximately (A) 0° (B) 4° (C) 10° (D) 15° (E) 19° Source: Master GMAT

rajatchopra1994 · Answer

Explanation:

For City Y temperature was increasing while city X was decreasing were sept-oct and Nov- dec.
Sept-Oct.: City X average = 50, City Y = 46
Nov-Dec.: City X average = 36, City Y = 60.

City X average: (50+36)/2= 43
City Y average: (36+60)/2= 53

Average increase of 10 between City Y and City X.

IMO-C

thr3at · Answer

Hello Experts,

Can someone please give a solution to this.

Lord_Biplab · Answer

During the months of  September  through  January , the average temperature of  X  is reducing while that of  Y  is increasing.

Average daily temperature of  X  during this period (Sept.-Jan.) =  \frac{(60+30)}{2}  = 45  F .
Average daily temperature of  Y  during this period (Sept.-Jan.) =  \frac{(40+65)}{2}  = 52.5  F .

Difference of the averages = 7.5  F .
Closest option is 10  F .

So, I chose 10  F .

kingbucky · Answer

Why did you take the first and last temperatures and calculate average ? There was another temperature ' in the middle

Posted from my mobile device

Lord_Biplab · Answer

I know, but as the plots are pretty much straight I took the short cut.
If you take the average of the differences of the temperatures of  X  and  Y  for these four months it turns out to be approx. 10.5  F .

Difference for September to November  = 50 - 46 = 4  F .
Difference for November to January = 58 - 35 = 17  F .

Average difference =  \frac{(4+17)}{2}  = 10.5  F .

Nidhi060799 · Answer

simply calculate average for Sep to Dec of Y i.e. (40+ 55+ 65)/3 = 53, and same for X for Sept to Dec, i.e. 60+ 40+30)/3=43
Difference is 10

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During the time periods in which City Y’s average daily temperature

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During the time periods in which City Y’s average daily temperature

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