PASCAL 2017 Problem 21

Past Contests PASCAL 2017
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1

Each of the numbers 1,5,6,7,13,14,17,22,26 is placed in a different circle below. The numbers 13 and 17 are placed as shown.

Image
Jen calculates the average of the numbers in the first three circles, the average of the numbers in the middle three circles, and the average of the numbers in the last three circles. These three averages are equal. What number is placed in the shaded circle?

Answer Choices
A. 1
B. 5
C. 6
D. 7
E. 14