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Railways PYQCBT 1 2016

RRB NTPC · Question 22

If (2a - 3)^2 + (3b - 5)^2 + (4c - 7)^2 = 0, then find the value of √(4a + 3b + 4c). A. 6√2 B. 9√2 C. 12√2 D. 3√2

  1. C

  2. A

  3. B

  4. D

Show answer & explanation

Answer: (D) D

Explanation

A sum of squares is zero only if each term is zero: a = 3/2, b = 5/3, c = 7/4. Then 4a + 3b + 4c = 6 + 5 + 7 = 18 and √18 = 3√2.