IR Explained: Q19: City Temperatures

May 28, 2012

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This post is part of a series--IR Explained--that walks through the sample Integrated Reasoning questions provided in the latest edition of the GMAT Official Guide.

Table Analysis questions are data-heavy, and this one is no exception. Remember that you can spend up to three minutes per TA question, meaning that you can take a few moments to understand what information the table contains before jumping into the questions.

Here, we're given several cities along with their continent and three attributes of their weather conditions on a particular day: minimum temperature, maximum temperate, and weather conditions. Note that "weather conditions" fall into one of only a few categories, such as "cloudy" or "fine."

19A asks you to compare the "mean maximum temperature" for South American cities to that of Oceania cities. In other words, you need to find all the cities for each continent and then determine the mean of their maximum temperatures.

Don't forget that you have a sort function! Sort by continent, and you'll find all the Oceania cities and South American cities grouped together. There are only three South American cities, and they had max temperatures of 29, 29, and 38. The mean must be between 29 and 38. The two Oceania cities had max temps of 25 and 29, for a mean between 25 and 29. Without doing any calculations, it is clear that the mean maximum temperature of the South American cities was greater than that for Oceania cities. 19A is Yes.

19B refers to the cities reporting "fine" weather. Use the sort function again, organizing by weather conditions to isolate the "fine" weather cities. There are seven such cities, and they reported max temperatures between 5 and 30. Thus, no city reporting fine weather had a max temp below 0. 19B is No.

Sort again by continent to handle 19C. The minimum temperatures of the eight Asian cities are, in order: -3, -3, 3, 3, 21, 22, 24, 26. Since there is an even number of Asian cities, the median is the mean of the two middle numbers. The mean of 3 and 21 is 12, so 19C is Yes.

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About the author: Jeff Sackmann has written many GMAT preparation books, including the popular Total GMAT Math, Total GMAT Verbal, and GMAT 111. He has also created explanations for problems in The Official Guide, as well as 1,800 practice GMAT math questions.

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