SSC CGL 2018 PYQ — Question 82

SSC CGL Tier II Quant - 19/02/2018 • Quantitative Aptitude • Q82

If the roots of the equation a(b – c)x2 +b(c – a)x + c(a – b) = 0 are equal, then which of the following is true?

Show answer & explanation

Correct answer: B

Explanation

The correct answer is option 2 i.e. 2/b = (1/ a) + (1/ c)

a(b - c)x2 + b(c - a)x + c(a - b) = 0

On putting x = 1, the equation is satisfied α = 1

Now, since it is given that both roots are equal

so, β = 1

α + β = 2

-b(c - a)/[a(b - c)] = 2

-bc + ab = 2ab - 2ac

2ac = ab + bc

Dividing both sides by abc

2/b = (1/a) + (1/c)