Let n bottles are needed to empty the bowl,
Therefore,
Volume of bowl = Volume of 'n' bottles
For hemispherical bowl,
Radius, r = 9 cm
As we know,
Volume of a hemispherical bowl = 2/3πr3
Where r is the radius of hemisphere
Volume of bowl
For single cylindrical bottle,
Base radius, r = 1.5 cm
Height, h = 4 cm
As we know,
Volume of cylinder = πr2h
Where r is base radius, h is height of cylinder.
Volume of one bottle = π(1.5)2(4) = 9π cm3
As,
Volume of bowl = volume of n bottles
486π = (9π)n
n = 486/9 = 54
Hence, 54 bottles are needed to empty the bowl.