Question 447452
External volume - Internal volume)( * density = weight of sphere

4/3 pir^3= volume
r1= 30
r2=20
4/3pi(r1^3-r2^3)= volume of shell
4/3 * pi ( 27000-8000)
4/3 * pi *19000
== 79,587.01 cu.cm

....
Density = 7.8gms/cu.cm
79,587.01*7.8=620,778 gms

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