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SSC CGL 2018 PYQ — Question 34

SSC CGL Tier II Quant - 09/03/2018 • Quantitative Aptitude • Q34

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A hollow cylinder has height 90 cm and the outer curved surface area is 11880 cm2. It can hold 55440 cm3 of air inside it. What is the thickness (in cm) of this cylinder?

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Correct answer: C

Explanation

The correct answer is option 3 i.e. 7

Let say, radius of inside of cylinder = r cm.

So, πr2h = 55440.

or, r = 14. (h = 90 cm)

Let say, Curved surface area = 2πh (R + r)

So, 2πh (R + r) = 11880.

or, (R + r) =  =  = 21

So, R = 21 − r = 21 − 14 = 7.

Thickness of cylinder is 7 cm.

C is correct choice.