The height of a solid cylinder in 30 cm and the diameter of its base is 10 cm. Two identical conical holes each of radius 5 cm and height 12 cm are drilled out. What is the surface area (in cm2) of the remaining solid?
A. 430π
B. 230π
C. 330π
D. 120π
Answer: Option A
Solution (By Examveda Team)
L.S.A. of cylinder = 2πrh
= 2 × $$\frac{{22}}{7}$$ × 5 × 30
= 300π
L.S.A. of cones = 2[πr$$l$$]
= 2[π × 5 × 13]
= 130π
T.S.A. of remaining part
= 300π + 130π
= 430π
This Question Belongs to Arithmetic Ability >> Mensuration 3D
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