Question 73

If x : y : z = 1 : 2 : 3, then what the value of $$\left(\frac{3x^{2}-2y^{2}+4z^{2}}{x^{2}+2y^{2}+z^{2}}\right)$$

Solution

Given, 

x : y : z = 1 : 2 : 3 

Let x = a 

y = 2a 

z = 3a

Putting these value in the equation given in question : 

$$\therefore\ \left(\frac{3x^2-2y^2+4z^2}{x^2+2y^2+z^2}\right)$$
$$\therefore\ \frac{3a^2-2\left(2a\right)^2+4\left(3a\right)^2}{a^2+2\left(2a\right)^2+\left(3a\right)^2}$$

$$\therefore\ \frac{3a^2-8a^2+36a^2}{a^2+8a^2+9a^2}$$

$$\therefore\ \frac{31a^2}{18a^2}$$

$$\therefore\ \frac{31}{18}$$

Hence, Option C is correct. 


Create a FREE account and get:

  • Free SSC Study Material - 18000 Questions
  • 230+ SSC previous papers with solutions PDF
  • 100+ SSC Online Tests for Free

cracku

Boost your Prep!

Download App