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SSC CGL 2024 PYQ — Question 72

SSC CGL - 12 Sep 2024 - Shift 3 • Quantitative Aptitude • Q72

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 Which of the following is the sum of the values of a and b if the equations 2x + y = a, 8x + by = 12 have infinite solutions?

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Correct answer: C

Explanation

The correct answer is option 3 i.e. 7.

⇒ 2x + y = a
⇒ 8x + by = 12
⇒ 28=1b=a12\frac{2}{8} = \frac{1}{b} = \frac{a}{12}
 solve for (b):

⇒ 28=1b⇒b=4\frac{2}{8} = \frac{1}{b} \quad \Rightarrow \quad b = 4
solve for (a):

⇒ 28=a12⇒a12=14⇒a=3\frac{2}{8} = \frac{a}{12} \quad \Rightarrow \quad \frac{a}{12} = \frac{1}{4} \quad \Rightarrow \quad a = 3

⇒ a + b = 3 + 4 = 7
The sum of the values of (a) and (b) is (7).