If (4x2 - 3y2) : (2x2 + 5y2) = 12 : 19, then x : y is
A. 2 : 3
B. 1 : 2
C. 3 : 2
D. 2 : 1
Answer: Option C
Solution(By Examveda Team)
$$\eqalign{ & {\text{ = }}\frac{{4{x^2} - 3{y^2}}}{{2{x^2} + 5{y^2}}} = \frac{{12}}{{19}} \cr & \Rightarrow 19\left( {4{x^2} - 3{y^2}} \right) = 12\left( {2{x^2} + 5{y^2}} \right) \cr & \Rightarrow 76{x^2} - 57{y^2} = 24{x^2} + 60{y^2} \cr & \Rightarrow 52{x^2} = 117{y^2} \cr & \Rightarrow 4{x^2} = 9{y^2} \cr & \Rightarrow \frac{{{x^2}}}{{{y^2}}} = \frac{9}{4} \cr & \Rightarrow {\left( {\frac{x}{y}} \right)^2} = {\left( {\frac{3}{2}} \right)^2} \cr & \Rightarrow \frac{x}{y} = \frac{3}{2} \cr & \therefore x:y = 3:2 \cr} $$Related Questions on Ratio
If a : b : c = 3 : 4 : 7, then the ratio (a + b + c) : c is equal to
A. 2 : 1
B. 14 : 3
C. 7 : 2
D. 1 : 2
If $$\frac{2}{3}$$ of A=75% of B = 0.6 of C, then A : B : C is
A. 2 : 3 : 3
B. 3 : 4 : 5
C. 4 : 5 : 6
D. 9 : 8 : 10
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