4. There are two water tanks. Tank A and Tank B. At the onset of the situation, Tank A is empty and begins to be filled at a rate of 2 gallons per minute. At the same time, Tank Bhas in it, 140 gallons, and begins to be drained at a rate of 5 gallons per minute. Write a system of equations to model this situation, where x represents the minutes. Determine the number of minutes until the tanks have the same amount of water. How many gallons of water do each of the tanks have? ​