Bunuel wrote:
12 litres of water are poured into an aquarium of dimensions 50cm length, 30cm breadth, and 40cm height. How high (in cm) will the water rise?
(1 litre = 1000cm³)
A. 6
B. 8
C. 10
D. 20
E. 40
we have 1 litre = 1000cm³ (thanks Bunuel)
=>12 litres = 12*1000 = 12000cm³
Let call the height of the water is x
the breadth and length of the water will equal the aquarium
The volume of the water:
50 * 30 * x = 12000cm³
=> x = 12000/(50*30) = 8 cm
Answer is B
Another solution:Let call the height of the space that doesn't contain water is x
First we must find the volume of the aquarium:
50 * 30 * 40 = 60000 cm³
The volume of the space that doesn't contain water :
60000-12000 = 48000 cm³
The height of the space:
50 * 30 * x = 48000 cm³
=> x = 48000/(50*30) = 32
The height of the water:
the height of the aquarium - x = 40 -32 = 8cm
Answer is B