Find the number of solid spheres, each of diameter 6 cm, that could be moulded to form a solid metallic cylinder of height 45 cm and diameter 4 cm.
Solid sphere volume v=43πr3
rv=43×227×33cm3
rv=4×π×9=36πcm3
Volume of cylinder =πR2h=π×(42)2×45cm
or v=180πcm3
n= no of spheres =vv=180πcm336πcm3
⇒n=5