The figure shows an empty transparent tank made from three containers. The two containers V and W on top are in the form of cuboids which have square bases of side 7 cm and 3 cm as shown in the figure. The bottom container is in the form of a cube of side 12 cm. 2.25 ℓ of water are poured into the empty vase. Find the height of the water level from the base of the vase. (1 litre = 1000 cm³)
Volume of the bottom container
= 12 x 12 x 12
= 1728 cm³ 

Base area of container V
= 7 x 7
= 49 cm²

Base area of container W
= 3 x 3
= 9 cm²

Combined base areas of the containers on top
= 49 + 9
= 58 cm²

2.25 ℓ = 2250 mℓ

Volume of water inside the containers on top only
= 2250 - 1728
= 522 mℓ

Height of water of the containers on top only
= 522 ÷ 58
= 9 cm

Total height of water level
= 12 + 9
= 21 cm

Answer(s): 21 cm