posted by Voh .
The spring runoff from melting snow from a certain region is being accumulated in a reservoir. The reservoir is 450 yards long; and its ross-section is an isosceles triangle 40 yards wide at the top and 20square root(3) yards high. Water is flowing into the reservoir at the rate of 200 cubic yards per hour and, simultaneously, water is leaking out from the reservoir at the rate of 50 cubic yards per hour. Find the rate at which the level of the water is rising when the depth of water is 10squareroot(3) yards.