CBSE Class 10 Answered

Ans 1

Volume of B in the solid = Volume of cone = πr²h/3 = (22/7)(3/2)(3/2)(8/9) = 6.28 cm³

Volume of cylinder = πR²H = (22/7)(5)(5)(5) = 39.81 cm³

Volume of A in the solid = Volume of cylinder - Volume of cone = 39.81 - 6.28 = 33.53

Volume of metal A/Volume of metal in the solid = 33.53/6.28 =  5.34

Ans 2

Volume of bigger sphere = Total Volume of smaller spheres

Volume = Mass/Density.

Volume of 1 kg = 1/Density = πd³/6

Hence Density = 1/(πd³/6)

Volume of 7 kg = 7/Density.

Total volume = 8/Density = πD³/6           ... D is the diameter

 πD³/6 = 8/(1/(πd³/6)) = 8πd³/6

D³ =  8d³ = 8x3x3x3 = 2x2x2x3x3x3

D = 6 cm.

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