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Source: — Problem Solving |

by aneesh.kg » Thu May 31, 2012 11:53 am
phoenix9801 wrote:4-
The average (arithmetic mean) of 20, 60, and 100 is 10 more than the average of 40, 80, and which of the following?

A) 110
B) 90
C) 70
D) 50
E) 30
Let the unknown number be x. Then

(20 + 60 + 100)/3 = (40 + 80 + x)/3 + 10
60 = 40 + x/3 + 10
x = 30

[spoiler](E)[/spoiler] is correct.
Aneesh Bangia
GMAT Math Coach
[email protected]

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