SOLUTION: The mean of 4 numbers is 70 when a fifth number is included the mean of the five numbers is 80. What is the fifth number ?
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Question 867034: The mean of 4 numbers is 70 when a fifth number is included the mean of the five numbers is 80. What is the fifth number ? Answer by lenny460(1073) (Show Source):
You can put this solution on YOUR website! The mean of 4 numbers is 70 when a fifth number is included the mean of the five numbers is 80. What is the fifth number ?
70 * 4 = 280
80 * 5 = 400
Therefore:
400 - 280 = 120
