A students average (arithmetic mean) test score on 4 tests is 78. What must be the student's score on a 5th test for the student's average score on the 5 tests to be 80?
2 Explanations
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Chitrabhanu Dasgupta
I thought in a different way:
To reach an avg of 80, 4 guys are lacking { (80 - 78) * 4 } number i.e. 8 numbers
5th guy must score this extra numbers along with his 80 to cover the deficit i.e. 80 + 8 = 88
2 Explanations