In an examination of 4 subjects, John gets 100, 60 and 55 in three subjects. If his average (arithmetic mean) marks for all four subjects is 75, then the marks in the 4th subject must be
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✓ Correct answer: A. 85The average marks for all four subjects is 75 and so total marks are 4 x 75 = 300<br/><br/>The marks for three subjects are given and their total is 100 +60 + 55 = 215. Hence the marks for the fourth subject = 300- 215 = 85<br/><br/><b>Key takeaway: </b>GMAT always refers to an average as average (arithmetic mean) The average ( arithmetic mean ) of a set of numbers is their sum divded by the number of numbers in the set. For average problems, think Total divided by number of items.
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