Question

1. A cylindrical tube opened at both the ends is made of iron sheet which is 2cm thick. If the outer diameter is 16cm and its length is 100 cm, find how many cubic centimeters of iron have been used in making the tube.

Answer 1

Let there are two cylinders of radii r and R.
Here R=16/2=8cm
and, r=8-2=6cm
Height of the cylinder =10cm
Volume of big cylinder =22/7 * 8*8*10
=2011.24 cm3
Now,
Volume of small cylinder =22/7*6*6*10=1131.24 cm3
Volime of iron used= 2011.24-1131.24
=880cm3