If eleven consecutive integers are listed from least to greatest, what is the average (arithmetic mean) of the eleven integers?
1.The average of the first nine integers is 7
2. The average of the last nine integers is 9
Ans. D
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GMAT Prep Test 2
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jayhawk2001
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Sum of series a1, a2...an = n/2 (2a + (n-1)d)
Average = 1/2 (2a + (n-1)d)
1 - sufficient.
1/2 (2a1 + 8) = 7. We can find a1 and hence we can find average of
11 consecutive integers starting with a1
2 - sufficient. Same as 1
Hence D.
Average = 1/2 (2a + (n-1)d)
1 - sufficient.
1/2 (2a1 + 8) = 7. We can find a1 and hence we can find average of
11 consecutive integers starting with a1
2 - sufficient. Same as 1
Hence D.
