Question 471026
Add the two given scores with the missing score, divide by 3, and that is the average.  Assuming, everything is weighted the same.


65 + 75 + x
------------ = 80 
3


140 + x
------- = 80 {combined like terms in numerator}
3


140 + x = 240 {multiplied both sides by 3}
x = 100 {subtracted 140 from both sides}


He must receive 100% on the test.
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