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SSC CGL 2020 PYQ — Question 56

SSC CGL Tier II - Quant - 15 Nov 2020 • Quantitative Aptitude • Q56

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The graphs of the equations 3x - 20y - 2 = 0 and 11x - 5y + 61 = 0 intersect at P(a,b). What is the value of (a2 + b2 - ab)/(a2 - b2 + ab)?

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Correct answer: C

Explanation

  The correct answer is option 3 i.e. 3141\frac{31}{41}

Application

3x - 20y = 2

11x - 5y = - 61

Upon solving this equation

41x = -246

x = - 6

putting the value of x = -6 in any of the equation, we will get 

y = -1

both the equations intersect each other at point P(a, b) = P(x. y)

a = -6 and b = -1

(a2 + b2 - ab)/(a2 - b2 + ab) = (36 + 1 - 6)/(36 - 1 + 6)

31/41