cuboid fish tank is 50 cm long, 30 cm wide, and 40 cm high when measured from the inside, and the water surface is 5 cm away from the mouth of the tank. How many liters of water are there in the fish tank?
一个长方体鱼缸，从里面量长50厘米，宽30厘米，高40厘米，水面离缸口边5厘米．鱼缸内共有水多少升？
<result>52.5</result>