back 20 of 25 skip Water is draining out of a conical tank at a constant rate of 120 cubic inches per minute. How fast is the level of O The level of water in the tank is decreasing at a rate of 9.4 inches per minute. water in the tank decreasing when there are 7 inches of water in the tank? O The level of water in the tank is decreasing at a rate of 3.1 inches per minute 15 inches O The level of water in the tank is decreasing at a rate of 0.8 inches per minute. O There is not enough information given. 30 inches 7 inches 120 cubic inches per minute HINT: Use the formula for the volume of a cone, V = - mr2h, where r is the radius of the cone and h is the height of the cone, but writer in terms of h. Notice that the radius of the cone will always be 1/2 the height because the cone of water is always similar to the tank itself. Therefore, r = h and V = lurch = ()h= Lwh3