A rectangular tank 25 cm long and 20 cm wide contains water to a depth of 5 cm. A
metal cube of side 8 cm is placed in the tank so that the face of the
cube rests on the bottom of the tank. How much water must be poured into
the tank so as to just cover the cube?

1) 1000
2) 847
3) 768
4) 988
5) 625