Aptitude - Area - Discussion
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Read more:"You cannot shake hands with a clenched fist."
- Indira Gandhi
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An error 2% in excess is made while measuring the side of a square. The percentage of error in the calculated area of the square is:
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2% | [B]. |
2.02% | | [C]. |
4% | [D]. |
4.04% |
Answer: Option B
Explanation:
100 cm is read as 102 cm.
 A1 = (100 x 100) cm2 and A2 (102 x 102) cm2.
(A2 - A1) = [(102)2 - (100)2]
= (102 + 100) x (102 - 100)
= 404 cm2.
| Percentage error = |
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404 |
x 100 |
 % |
= 4.04% |
| 100 x 100 |
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Ramesh said:
(Sun, Mar 6, 2011 11:24:41 PM)
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| Sir Percentage error is not understanding. Please solve the answer. |
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Sakshi said:
(Mon, Mar 7, 2011 02:13:49 AM)
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We can also get the percentage by this.
Percentage error = 404/100 = 4.04 |
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Anbu said:
(Sun, Dec 4, 2011 05:51:33 PM)
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(A2 - A1) = [(102)2 - (100)2] How it come?
Please advise |
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Amrita said:
(Sat, Dec 10, 2011 08:09:56 PM)
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| To find out error we got to subtract it first. |
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Shreya Singh said:
(Fri, Feb 3, 2012 02:51:24 PM)
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In this type of % some usefull idea is to take default no as 100 and in question 2% is error. Hence our no is 100 error no is 102.
So solve further with square formula:
Area= (side)* (side) |
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Mazher said:
(Wed, Feb 8, 2012 11:32:07 PM)
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| Why we are taking this three 100's ? |
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