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The average of five numbers is 60. If one of them is changed to 80, then the average of the five numbers will be 70. What is the original value of this change?
The original number was 30
The average of five numbers is 60. If one of them is changed to 80, the average will be 70. What is the original number?
70 × 5-60 × 5 = 350-300 = 5080-50 = 30
The average of five numbers is 60. If one of them is changed to 80, the average will be 70. What is the original number?
70 × 5-60 × 5 = 350-300 = 5080-50 = 30
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