Hydrology and Runoff

A 1-hour unit hydrograph has ordinates $U_1 = 10\text{ m}^3/\text{s}$ and $U_2 = 25\text{ m}^3/\text{s}$. Two successive 1-hour rainfall excess blocks are $P_1 = 2.0\text{ cm}$ and $P_2 = 1.0\text{ cm}$. Direct runoff at the second hour $Q_2 = P_1 U_2 + P_2 U_1 = 2(25) + 1(10)$ in $\text{m}^3/\text{s}$ is: