起初，水箱 A 装满了水，水箱 B 装了 $\frac{1}{5}$ 的水。 弗雷德（Fred）同时打开了水龙头 X 和 Y。水从水箱 A 流出，并以相同的速度（每分钟 6 升）流入水箱 B。 过了一会儿，当两个水箱的水位高度相同时，弗雷德关闭了两个水龙头。 最后水箱 A 的水位高度是多少？ 答案: ___

1. Calculate the base areas of Tank A and Tank B.

Base area of Tank A $= 80 \times 30 = 2400 \text{ cm}^2$
Base area of Tank B $= 50 \times 40 = 2000 \text{ cm}^2$

2. Calculate the initial volume of water in Tank A and Tank B.

Initial volume in Tank A $= 2400 \times 56 = 134400 \text{ cm}^3$
Initial height in Tank B $= \frac{1}{5} \times 60 = 12 \text{ cm}$
Initial volume in Tank B $= 2000 \times 12 = 24000 \text{ cm}^3$

3. Determine the total volume of water in both tanks.

Since water flows out of Tank A at $6$ litres per minute and into Tank B at $6$ litres per minute, the total volume of water in both tanks remains constant.
Total volume $= 134400 + 24000 = 158400 \text{ cm}^3$

4. Calculate the final height of the water level.

Let the final height be $h$ cm.
Final volume in Tank A + Final volume in Tank B $= 158400$
$2400h + 2000h = 158400$
$4400h = 158400$
$h = \frac{158400}{4400} = 32 \text{ cm}$