A tank is rectangular in plan measuring $10$mby $4$m at the base. The cross$-$section of the tank istrapezoidal. The $10$m long sides slope outwardsfrom the base at an angle of $45,$ while the ends ofthe tank are vertical. A triangular weir with q$/2=50$ is cut out of one of the vertical ends with thebottom of the V being at the same level as thebase of the tank. Its CD is $0\mathrm{.}58.$ The water level inthe tank is initially $1\mathrm{.}3$m above the base of thetank, and has to be reduced to $0\mathrm{.}1$m$.$ Assuming