UPTET Paper 1 2019 Solved Paper

Concept:If three equal ratios have the same value, we can set each fraction equal to that common value and then add the resulting equations. Explanation:Let $\frac{a+b}{c}=K$, $\frac{b+c}{a}=K$, and $\frac{c+a}{b}=K$. Write each as an equation: $a+b=Kc$, $b+c=Ka$, $c+a=Kb$. Add all three equations: $(a+b)+(b+c)+(c+a)=Kc+Ka+Kb$. Left side simplifies to $2(a+b+c)$. Right side is $K(a+b+c)$. So $2(a+b+c)=K(a+b+c)$. If $a+b+c\neq0$, divide both sides by $(a+b+c)$ to get $K=2$. (If $a+b+c=0$, then each fraction equals $-1$, but the given options do not include $-1$; hence the consistent value is $2$.) Answer:C. 2