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Aptitude · Q126

Mensuration 3d

Competitive Exams · Aptitude · question 126

Q126

A solid cylinder has total surface area of 462 sq. cm. Its curved surface area is one third of the total surface area. Then the radius of the cylinder is

A.
7 cm
Answer
B.
3.5 cm
C.
9 cm
D.
11 cm

Answer: Option A

Solution

Answer: Option A
Solution:
According to the question
Curved surface area = × Total surface area
2πrh = × 2πr(h + r)
h = 2r . . . . . . (1)
Now total surface area = 2πr(h + r) = 462
By using equation - (1)
2πr(2r + r) = 462
r = 7 cm