Aptitude - Volume and Surface Area - Discussion
Discussion Forum : Volume and Surface Area - General Questions (Q.No. 5)
5.
A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3, then the weight of the pipe is:
Answer: Option
Explanation:
External radius = 4 cm,
Internal radius = 3 cm.
| Volume of iron |
|
||||||
|
|||||||
| = 462 cm3. |
cm3
Weight of iron = (462 x 8) gm = 3696 gm = 3.696 kg.
Discussion:
60 comments Page 6 of 6.
Gopal said:
1 decade ago
How to convert gm to kg ?
Manojit said:
1 decade ago
As the thickness of the pipe is 1 cm.....
Anju said:
1 decade ago
Why internal radius is 3?
Sandeep said:
1 decade ago
Because external diameter is 8cm then.
External radius is 8/2=4cm.
External radius is 8/2=4cm.
Krishna said:
1 decade ago
Why external radius is 4cm how is it ?
Mobi001 said:
1 decade ago
Thats fine. I understood the logic.
Because from both side the 1cm will be deducted.
Because from both side the 1cm will be deducted.
Mobi001 said:
1 decade ago
If the thickness of pipe is 1 cm the internal diameter should not be 7 cm if yes then internal radius must be 3.5 ?
Divya said:
1 decade ago
Why [4]^2-[3]^2 while calculating volume?
Neelam shelke said:
1 decade ago
Thickness of the pipe is 1cm, and external radius is 4cm, so 4-1=3, thus the internal radius is 3, as per my thinking.
Anupam Tripathi said:
1 decade ago
Why internal radius is 3 cm?
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