Consider a three-firms oligopoly market with a linear demand function given by \( P = 25 - Q \), where \( P \) is the unit price and \( Q \) is the total quantity supplied. The total quantity \( Q = q_1 + q_2 + q_3 \), where \( q_i \) is the output from the \( i^{th} \) firm with \( i = 1,2,3 \). The total cost (TC) curve of firm \( i \) is given by \( TC_i = \alpha_i + 5q_i \), where \( \alpha_i \)'s are positive real numbers. Assuming a Cournot solution exists, the value of \( Q \) is: