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There is four number average of the first three is 15 and that of the last three is 16 if the last number is 19 find the first number?

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There is four number average of the first three is 15 and that of the last three is 16 if the last number is 19 find the first number? Answer: 16

Given information: The average of the first three numbers (A, B, C) is 15 A+B+C​/3=15 A+B+C=45 The average of the last three numbers (B, C, D) is 16 B+C+D/3​=16 B+C+D=48 The last number (D) is 19 B+C+19=48 B+C=29 Finding A We already have: A+B+C=45 Substituting B+C=29: A+29=45 A=45−29 A=16

Question context

This question is part of 🧩 Logical Reasoning within the broader 🧠 Aptitude Mastery subject and appears in the ASF Airports Security Force preparation collection. Reviewing the answer together with nearby questions helps reinforce the underlying concept and identify how it may appear in competitive exams.