Question

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1. 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 four walls, the volume of the hall is:
A. 720
B. 900
C. 1200
D. 1800
See Answer
2. A cylindrical jar of radius 15 cm is filled with water up to a height of 25 cm. 15 spherical
balls of radii 2 cm each are immersed in the jar. Find the new level to which water is filled in​

Answer 1

Answer:

1) Volume= 1200

2) New height = 25.7

Step-by-step explanation:

1) Let the height of hall = h

Area of floor + Area of ceiling = Areas of walls

(15*12) + (15*12) = 12h +15h +12h + 15h

360= 54h

therefore h= $\frac{20}{3}$

Hence, Volume of hall =  $\frac{20}{3}$ * 15* 12 =1200

2) Let V1 = Volume of water before adding spheres

V1 = π (225)(25) = 5625π

V (all spheres) = 15 *($\frac{4}{3}$ *π * 8) = 160π

V2 = Volume after adding spheres

V2= 160π + 5625π = 5785π

therefore ,π$r^{2}$h= 5785π

h= (5785/225) = 25.7 cm