Q21. A rectangular water tank is 80 m x 40 m. Water flows into it through a pipe of 40 sq.cm at the opening at a speed of 10 km/hr. By how much, the water level will rise in the tank in half an hour ?
A. 3/2 cm
B. 4/9 cm
C. 5/8 cm
D. 3/5 cm
Q22. The number of bricks, each measuring 25 cm ×12.5 cm×7.5 cm, required to construct a wall 6m long, 5m high and 0.5 m thick ,while the mortar occupies 5% of the volume of the wall, is:
A. 8120
B. 6080
C. 3040
D. 5740
Q23. The cost of the paint is Rs. 36.50 per kg. If 1 kg of paint covers 16 square feet, how much will it cost to paint outside of a cube having 8 feet each side.
A. 692
B. 972
C. 768
D. 876
Q24. The length of an edge of a hollow cube open at one face is √3 metres. What is the length of the largest pole that it can accommodate ?
A. 8 metres
B. 12 metres
C. 3 metres
D. 6 metres
Q25. The edges of a cuboid are in the ratio 1 : 2 : 3 and its surface area is 88 sq cm. The volume of the cuboid is:
A. 24
B. 48
C. 64
D. 120
Q26. The cost of painting the whole surface area of a cube at the rate of 13 paise per sq. cm is Rs 343.98. Then the volume of the cube is:
A. 9261
B. 9250
C. 14400
D. 44200
Q27. A cube of edge 5 cm is cut into cubes each of edge 1 cm. The ratio of the total surface area of one of the small cubes to that of the large cube is equal to:
A. 1 : 25
B. 1 : 5
C. 1 : 625
D. 1 : 125
Q28. An iron cube of side 10 cm is hammered into a rectangular sheet of thickness 0.5 cm. If the sides of the sheet are in the ratio 1 : 5, the sides are :
A. 10 cm, 50 cm
B. 20 cm, 100 cm
C. 40 cm, 200 cm
D. 60 cm, 300 cm
Q29. A cuboidal block 6cm x 9cm x 12cm is cut up into an exact number of equal cubes.The least possible number of cubes will be:
A. 6
B. 9
C. 24
D. 30
Q30. Three cubes with sides in the ratio 3 : 4 : 5 are melted to form a single cube whose diagonal is  cm. The sides of the cubes are :
A. 6 cm, 8 cm, 10 cm
B. 3 cm, 4 cm, 5 cm
C. 7 cm, 4 cm, 14 cm
D. 9 cm, 12 cm, 15 cm
