design a hydraulic holding system for a hay-baling system, the system has four cylinders with a 120mm diameter pistons with a stroke of 0.320m, the lines connecting the system are 1cm id(inside diameter). there are 15.5m of lines in the system. for proper design, the reserve tank should hold a minimum of 50% more then the amount of hydraulic fluid in the system, if the diameter of the reserve tank is 30.48cm what is the shortest height it should be?

This question I' am completely stuck on, I have no idea were to start, any pointers would be great

I have the answer but i have no idea how they got it