Electronic Journal of Differential Equations, Vol. 2008(2008), No. 157, pp. 1-8. Title: Explicit solutions for a system of first-order partial differential equations Author: Kayyunnapara Thomas Joseph (Tata Institutei, Mumbai, India) Abstract: In this paper we construct explicit weak solutions of a system of two partial differential equations in the quarter plane $\{(x,t):x>0,t>0\}$ with initial conditions at $t=0$ and a weak form of Dirichlet boundary conditions at $x=0$. This system was first studied by LeFloch [9], where he constructed explicit formula for the weak solution of pure initial value problem. Submitted November 1, 2008. Published November 20, 2008. Math Subject Classifications: 35A20, 35L50, 35R05. Key Words: First order equations; boundary conditions; exact solutions