SOLUTION: the average(arithmetic mean) of x and y is 5 and the average of x, y, and z is 8. What is the value of z?

Question 293242: the average(arithmetic mean) of x and y is 5 and the average of x, y, and z is 8. What is the value of z?

Answer by nerdybill(7384) (Show Source): You can put this solution on YOUR website!
the average(arithmetic mean) of x and y is 5 and the average of x, y, and z is 8. What is the value of z?
.
From:"the average(arithmetic mean) of x and y is 5" we get:
(x+y)/2 = 5 (equation 1)
.
From:"the average of x, y, and z is 8" we get:
(x+y+z)/3 = 8 (equation 2)
.
Solve equation 1 for (x+y):
(x+y)/2 = 5
Multiplying both sides by 2:
(x+y) = 10
.
Substitute the above into equation 2:
(x+y+z)/3 = 8
(10+z)/3 = 8
10+z = 24
z = 14
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