If (a + b) : (b + c) : (c + a) = 7 : 6 : 5 and a + b + c = 54, then what will be the value of \(\frac{1}{a}\) : \(\frac{1}{b}\) : \(\frac{1}{c}\) ?
Answer & explanation
Correct answer: option 2
(a + b) : (b + c) : (c + a) = 7 : 6 : 5 ......(ii)
Here, adding all,
⇒ 2(a + b + c) = 18R
⇒ (a + b + c) = 9R = 54
⇒ 1R = 6
We can find the value of a, b and c:
⇒ a + b + c = 9R .....(i)
(a + b) = 7R .....(ii)
(b + c) = 6R .....(iii)
(c + a) = 5R .....(iv)
After subtracting from (i);
a = 3R; b = 4R; c = 2R
a : b : c = 3 : 4 : 2
Now,
⇒ \(\frac{1}{a}\) : \(\frac{1}{b}\) : \(\frac{1}{c}\) = \(\frac{1}{3}\) : \(\frac{1}{4}\) : \(\frac{1}{2}\) = 4 : 3 : 6