**Question:**

A storage tank is in the form of a cube. When it is full of water, the volume of water is 15.625 m3. If the present depth of water is 1.3 m, then find the

volume of water already used from the tank.

**Solution:**

Let side of a cube be = x m

∴ Volume of cubical tank = 15.625 m3 [given]

=> x3 = 15.625 m3

=> x = 2.5 m

and present depth of water in cubical tank = 1.3 m

∴ Height of water used =2.5 – 1.3 m = 1.2 m

Now, volume of water used = 1.2 x 2.5 x 2.5= 7.5 m3

= 7. 5 x 1000 = 7500 L [∴ 1 m3 = 1000 L]

Hence, the volume of water already used from the tank is 7500 L.