1.  50 men took a dip in a water tank 40 m long and 20 m broad on a religious day. If the average displacement of water by a man is 4 m3, then the rise in the water level in the tank will be :

20 cm
25 cm
35 cm
50 cm

Option

Total volume of water displaced = (4 * 50) m3 = 200 m3 Rise in water level = (20040 * 20) m = 0.25 m= 25 cm

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2.  A boat having a length 3 m and breadth 2 m is floating on a lake. The boat sinks by 1 cm when a man gets on it. The mass of man is :

12 kg`
60 kg
72 kg
96 kg

Option

Volume of water displaced = (3 * 2 * 0.01) m3 = 0.06 m3. Mass of man = Volume of water displaced * Density of water. = (0.06 * 1000) kg = 60kg.

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3.  A cistern 6 m long and 4 m wide contains water up to a depth of 1 m 25 cm. The total area of the wet surface is:

49 m2
50 m2
53.5 m2
55 m2

Option

Area of the wet surface = [ 2(lb + bh + lh) - lb] = 2 (bh + lh) + lb = [2 (4 * 1.25 + 6 * 1.25) + 6 * 4] m2 = 49 m2.

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4.  A cistern capacity 8000 litres measures externally 3.3 m by 2.6 m by 1.1 m and its walls are 5 cm thick. The thickness of the bottom is :

90 cm
1 dm
1 m
1.1 m

Option

Let the thickness of the bottom be x cm. Then, [(330 - 10) * (260 - 10) * (110 - x) = 8000 * 1000. 320 * 250 * (110 - x) = 8000 * 1000 (110 - x) = 8000 * 1000320 * 250 = 100. x = 10 cm = 1 dm.

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5.  A hall is 15 m long and 12 m broad. If the sum of the areas of the floor and the ceiling is equal to the sum of the areas of the four walls, the volume of the hall is :

720
900
1200
1800