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A flask in the shape of a right circular cone of height 36 cm is completely filled with tea. The tea is then poured into another right circular cylindrical flask whose radius is two-third of the radius of base of the circular cone. Then, the height of the tea in the cylindrical flask is

Solution

✅ Correct Option: 1

A flask in the shape of a right circular cone of height 36 cm is completely filled with tea. The tea is then poured into a cylindrical flask whose radius is two-third of the radius of the base of the cone.

Let the radius of the conical flask be rr and the radius of the cylindrical flask be R=2r3R = \frac{2r}{3}.

Let the height of tea in the cylindrical flask be HH.


The volume of tea remains constant when poured from one flask to another.

Volume of cone =13πr2h= \frac{1}{3}\pi r^2 h

=13×π×r2×36= \frac{1}{3} \times \pi \times r^2 \times 36

=12πr2= 12\pi r^2


Volume of cylinder =πR2H= \pi R^2 H

=π×(2r3)2×H= \pi \times \left(\frac{2r}{3}\right)^2 \times H

=π×4r29×H= \pi \times \frac{4r^2}{9} \times H

=4πr2H9= \frac{4\pi r^2 H}{9}


Since the volume of tea remains the same:

12πr2=4πr2H912\pi r^2 = \frac{4\pi r^2 H}{9}

12=4H912 = \frac{4H}{9}

108=4H108 = 4H

H=27H = 27

Therefore, the height of tea in the cylindrical flask is 27 cm.

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