SOLUTION: x+y =10 y+z = 15 x+z = 17 What is the average (arithmetic mean) of x, y and z ? (A) 21 (B) 17 (C) 15 (D) 7 (E) It cannot be determined from t

Algebra ->  Average -> SOLUTION: x+y =10 y+z = 15 x+z = 17 What is the average (arithmetic mean) of x, y and z ? (A) 21 (B) 17 (C) 15 (D) 7 (E) It cannot be determined from t      Log On


   

Question 253011: x+y =10 y+z = 15 x+z = 17

What is the average (arithmetic mean) of x, y and z ?
(A) 21 (B) 17 (C) 15 (D) 7 (E) It cannot be determined from the information given
Answer by hokies(65) About Me  (Show Source):
You can put this solution on YOUR website!
Add all 3 equations:
2x+2y+2z = 42
x+y+z = 21
(x+y+z)/3 = 7
The answer is 7