SOLUTION: Solve this equation:the average of X,Y and Z is 80. if twoo of the numbers are 74 and 78, then what is the other number?

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Question 892476: Solve this equation:the average of X,Y and Z is 80. if twoo of the numbers are 74 and 78, then what is the other number?
Answer by algebrahouse.com(1659) About Me  (Show Source):
You can put this solution on YOUR website!
x + y + z
----------- = 80 {to find average, add the numbers and divide by the number of numbers}
3

74 + 78 + z
------------ = 80 {substituted 74 and 78 for two of the numbers}
3

152 + z
-------- = 80 {added 74 and 78}
3

152 + z = 240 {multiplied each side by 3}
z = 88 {subtracted 152 from each side}

88 is the other number

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