Algebra

 

The average of 10 numbers is 85. If the numbers 70 and 78 are removed from the set of numbers,     

what is the average of the remaining numbers?     

 

Since the average of the 10 numbers is 85, the sum of the ten numbers is 850.  (i.e., 85 = ⁸⁵⁰/₁₀ ).   

 

Subtract 148 (i.e., remove 70 and 78) from that sum and the sum of the remaining 8 numbers is 702.     

 

The new average is given by 702 divided by 8.  Using a calculator, find that 87.75 is that new average.     

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