If we choose four numbers, the average of the first three will be 16 and that of last three is 15. If the last number is 18, the first number will be? A. 20 B. 21 C. 23 D. 25 Answer Workspace Report Discuss Answer with explanation Answer: Option B Explanation Sum of Last 3 numbers= 15*3=45 Hence the last number is 18 So, Sum of 2nd & 3rd = 45-18= 27 Again sum of first three numbers =16*3=48 Therefore the 1st number will be sum of 1st 3 number-sum of 2nd & 3rd number i.e. 48-27=21 Workspace
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