Aptitude - Area - Discussion
Discussion Forum : Area - General Questions (Q.No. 4)
4.
The percentage increase in the area of a rectangle, if each of its sides is increased by 20% is:
Answer: Option
Explanation:
Let original length = x metres and original breadth = y metres.
Original area = (xy) m2.
| New length = |  |
120 | x |  m |
= | |
6 | x | m. |
| 100 | 5 |
| New breadth = | |
120 | y | m |
= | |
6 | y | m. |
| 100 | 5 |
| New Area = | |
6 | x x | 6 | y | m2 |
= | |
36 | xy | m2. |
| 5 | 5 | 25 |
The difference between the original area = xy and new-area 36/25 xy is
= (36/25)xy - xy
= xy(36/25 - 1)
= xy(11/25) or (11/25)xy
 Increase % = |
|
11 | xy x | 1 | x 100 | % |
= 44%. |
| 25 | xy |
Video Explanation: https://youtu.be/I3jLjLPn1W4
Discussion:
74 comments Page 6 of 8.
Lexinah said:
1 decade ago
What if it says each side of a square not rectangle is increased by 15%?
What is the percentage area increase in its area?
What is the percentage area increase in its area?
Manan said:
1 decade ago
There is a much simpler method.
Suppose the length of rectangle = 100 cm & breadth = 50 cm.
So Area equals to 100*50 = 5000.
Now if 20% of both sides are increased then,
New length = 20% of 100 = 120 cm & 20% of 50 = 60 cm.
So, new area = 120*60 = 7200.
Difference = 7200-5000 = 2200.
Percentage increase = (2200\5000)*100 = 44%.
Suppose the length of rectangle = 100 cm & breadth = 50 cm.
So Area equals to 100*50 = 5000.
Now if 20% of both sides are increased then,
New length = 20% of 100 = 120 cm & 20% of 50 = 60 cm.
So, new area = 120*60 = 7200.
Difference = 7200-5000 = 2200.
Percentage increase = (2200\5000)*100 = 44%.
Lipu said:
1 decade ago
Let true area = (100)^2.
Error area = (120)^2.
So error %= (error area-true area)/true area.
= (120)^2-(100)^2/(100)^2 *100.
= 220*20/100.
= 44%.
Error area = (120)^2.
So error %= (error area-true area)/true area.
= (120)^2-(100)^2/(100)^2 *100.
= 220*20/100.
= 44%.
Hanny Gupta said:
1 decade ago
A1 = 100*100 = 10000.
A2 = 120*120 = 14400.
A2-A1 = 14400-10000 = 4400.
(A2-A1)% = 44 %.
A2 = 120*120 = 14400.
A2-A1 = 14400-10000 = 4400.
(A2-A1)% = 44 %.
Mani said:
1 decade ago
From where have we got new length and new breadth.
T.Pratap said:
1 decade ago
As you know that a square is also a rectangle.
We will suppose that its sides are l=100, b=100.
Thus the area will be= l*b = 100*100 = 10000.
Now if there.
Is increment of 20 %.
The new sides are l= 120 and b=120.
Thus the area will be = l*b = 14400.
Difference between the area before increment and after increment.
= 14400-10000 = 4400.
Now the % increase in area is = (4400/10000) *100 = 44%.
We will suppose that its sides are l=100, b=100.
Thus the area will be= l*b = 100*100 = 10000.
Now if there.
Is increment of 20 %.
The new sides are l= 120 and b=120.
Thus the area will be = l*b = 14400.
Difference between the area before increment and after increment.
= 14400-10000 = 4400.
Now the % increase in area is = (4400/10000) *100 = 44%.
Ram said:
1 decade ago
In a easy way.
Assume l & b = 10, 10.
Area = 10*10 = 100.
New length with 20% increase = 10*120/100 = 12.
So same as new breath with 20% increase = 12.
New area = 12*12 = 144.
Difference of both area = 44 %.
Assume l & b = 10, 10.
Area = 10*10 = 100.
New length with 20% increase = 10*120/100 = 12.
So same as new breath with 20% increase = 12.
New area = 12*12 = 144.
Difference of both area = 44 %.
Sandeepk said:
1 decade ago
I found below method most easy :
Let l=b=1 units.
Area = 1 * 1 = 1.
New l = b = 1.2 (20% increase).
New Area = 1.2 * 1.2 = 1.44.
Thus, 0.44 is 44% increase in area is the answer.
Let l=b=1 units.
Area = 1 * 1 = 1.
New l = b = 1.2 (20% increase).
New Area = 1.2 * 1.2 = 1.44.
Thus, 0.44 is 44% increase in area is the answer.
Sdasdasdad said:
1 decade ago
a=l*b=120l*120b.
a=14400lb.
a=100l*100b.
a=10000lb.
%=44/100.
44% answer.
a=14400lb.
a=100l*100b.
a=10000lb.
%=44/100.
44% answer.
Abhishek jain said:
1 decade ago
The percentage increase in the area of a rectangle, if each of its sides is increased by 20% is:::.
1. Suppose I have 10 of each side and then 20% increased of every side as a question now the 10 comes 12 so now, we have two sides one is new and one is old now we square both old and new sides and we receive 100 for old and 144 for new.
2. Now minus these numbers like.
(144-100) =44.
3. Now we will do percentage of 44 like.
Minus result/previous square nu. *100.
44/100*100=44 answer.
.
1. Suppose I have 10 of each side and then 20% increased of every side as a question now the 10 comes 12 so now, we have two sides one is new and one is old now we square both old and new sides and we receive 100 for old and 144 for new.
2. Now minus these numbers like.
(144-100) =44.
3. Now we will do percentage of 44 like.
Minus result/previous square nu. *100.
44/100*100=44 answer.
.
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