Step-by-step explanation: Each trough should be able to hold at least 200-300 litres of water with a minimum flow rates of 10 litres/minute. Trough volume can be reduced to about 100 litres if the flow rate is increased to 20 litres/minute. Likewise, how many gallons is a 2x2x4 tank?
Just plug the corresponding x value on the left of a,b,c, and d into the equation. If you don't understand the equation, it is asking you to multiply x by 3 and then subtract 2.