Question

27 solid iron spheres,each of radius x cm are melted to form a sphere with radius y cm ,find the ratio of x:y

Answer 1

Radius of 1 solid iron sphere =r

→ Volume =34πr3

→ Volume of 27 solid iron

spheres =27x34πr3

→ 34πr'3=27x34πr3

r'3=2πr3

→r'=3r

(ii) Surface area =4+πr2

SA r'=4πr'2

=4π(3r)2=36πr2

S'S=36πr24πr2=91=1:9