soumya_joy wrote:Let a, b and c are the sides of a triangle ABC. Given (a + b + c) (b + c - a) = kbc, then k
will lie between.
A. -1 and 1 B. -4 and 4 C. 0 and 4 D. 4 and 6
The proper mathematical approach for solving this problem is well beyond the reach of GMAT. So I'm going to solve this problem using picking number approach.
(a + b + c) is always positive and as the sum of two sides of a triangle is always greater than the third side, (b + c - a) is also positive. Hence, (a + b + c)(b + c - a) is always positive.
Hence, option A and B cannot be the answer.
Now, if we take a = b = c = 1, (a + b + c)(b + c - a) = 3
Hence, C is the only possible answer.
If anyone is looking for the mathematical approach see my next post.
