The difference between the outer and inner curved surface area of a hollow right circular cylinder 14cm long is 88cm2. If the volume of metal used in making the cylinder is 176cm3, find the outer and inner diameters of the cylinder. (Use π=22/7)
Outer curved surface area - Inner curved surface area =88
2πr(R−r)=88
R−r=882×227×14
R−r=88×72×22×14
R−r=1........(1)
Also we have
Volume of outer part - Volume of inner part =176
πh(R2−r2)=176
πh(R−r)(R+r)=176
π×14(R+r)=176
R+r=176×722×14
R+r=4......(2)
Adding (1) and (2), we get
R−r+R+r=5
2R=5
R=52
D=5
Putting in (2)
52+r=4
r=4−52
r=8−52
r=32
d=3