Question

If $(a+b):(b+c):(c+a)=5:6:9$ and $a+b+c=10$. What is the value of c?

• A. 2
• B. 3
• C. 5
• D. 7

Answer 1

The correct option is C 5

$\begin{array}{ccc}& (a+b):(b+c):(c+a)=5x:6x:9x& \\ and& a+b+c=10& \\ \Rightarrow & (a+b)+(b+c)+(c+a)=20x& \\ \Rightarrow & a+b+c=10x& \\ \Rightarrow & a+b+c=10& (\because x=1)\\ \therefore & c=(a+b+c)-(a+b)& \\ or& c=10-5=5& \end{array}$