Question

The line x = c cuts the triangle with vertices as (0, 0), (1, 1) and (9, 1) into two regions. For the area of the two regions to be same, c must be equal to

• A. $\frac{5}{2}$
• B. 3
• C. 7
• D. 3 or 15

Answer 1

The correct option is B 3

$2.\frac{1}{2}\left|\begin{array}{ccc}9& 1& 1\\ C& 1& 1\\ C& C/9& 1\end{array}\right|=\frac{1}{2}\left|\begin{array}{ccc}9& 1& 1\\ 1& 1& 1\\ 0& 0& 1\end{array}\right|=\frac{1}{2}\times 8=4$
on solving
C=3