Exam Pack 2 - ranges

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Exam Pack 2 - ranges

by lucas211 » Fri Jun 24, 2016 3:56 am
Hello BTG

How do we approach this problem?
Thanks in advance
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by GMATGuruNY » Fri Jun 24, 2016 4:37 am
The range for a list of measurements equals the greatest measurement minus the least measurement. The two lists of measurements, X and Y, combined consist of 30 measurements with a range of 25. What is the range for the measurements in list X?

1) The range for the 12 measurements in list Y is 20.

2) List X consists of 18 measurements.
Both statements are satisfied by the following cases:

Case 1:
least in Y = 1, greatest in Y = 21, range for Y = greatest - least = 21-1 = 20.
least in X = 21, greatest in X = 26, range for X = greatest - least = 26-21 = 5.
Since the least value in X and Y is 1, and the greatest value in X and Y is 26, the range for X+Y = 26-1 = 25.
In this case, the range for X = 5.

Case 2:
least in Y = 1, greatest in Y = 21, range for Y = greatest - least = 21-1 = 20.
least in X = 1, greatest in X = 26, range for X = greatest - least = 26-1 = 25.
Since the least value in X and Y is 1, and the greatest value in X and Y is 26, the range for X+Y = 26-1 = 25.
In this case, the range for X = 25.

Since X's range can be different values, the two statements combined are INSUFFICIENT.

The correct answer is E.
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by Krabhay » Tue Dec 18, 2018 9:11 pm
Lets say, the least number from the 2 lists is x. Then the biggest number from 2 lists will be (x + 25).
Statement 1: We cannot find the biggest and the smallest measurement in X from the given information. So, we cannot find the range of X. Hence, Insufficient.
Statement 2: No of measurements in list X doesn't alone provide us with the range of X. Hence, Insufficient.
Statement 1 & 2 together: Information given in both the statement doesn't help us in finding the range of X unless we are given that the smallest and the largest number of both the lists lie in X. Hence, Insufficient.

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by meenakshimiyer » Sat Jan 12, 2019 9:19 pm
Let's say, the least number from the 2 lists is x. Then the biggest number from 2 lists will be (x + 25).
Statement 1: We cannot find the biggest and the smallest measurement in X from the given information. So, we cannot find the range of X. Hence, Insufficient.
Statement 2: No of measurements in list X doesn't alone provide us with the range of X. Hence, Insufficient.
Statement 1 & 2 together: Information given in both the statement doesn't help us in finding the range of X unless we are given that the smallest and the largest number of both the lists lie in X. Hence, Insufficient.