SSC CPO 2019 PYQ — Question 108

The correct answer is option 1 i.e. 24.

Given:

x + y + z = 1, xy + yz + zx = – 26 and

x³ + y³ +z³ = 151

Use the formula:

(x + y + z)² = x² + y² + z² + 2(xy + yz + zx)

And

x³ + y³ + z³ – 3xyz = (x + y + z) (x² + y² + z² – (xy + yz + zx))

Using formula:

1² = x² + y² + z² + 2 × -26

x² + y² + z² = 53

And

151 – 3xyz = 1 × (53 – (-26))

3xyz = 151 – 79 = 72

xyz = 24