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 2 of 8.
AKASH SONI said:
1 decade ago
Its a lengthy approach
let length=L Breadth=b
intial area =L*B
increased length and breadth are 1.2L and 1.2B respectively
new area =1.44LB
increase area =.44lb
increased percentage area =.44LB/(LB)*100 =44%
let length=L Breadth=b
intial area =L*B
increased length and breadth are 1.2L and 1.2B respectively
new area =1.44LB
increase area =.44lb
increased percentage area =.44LB/(LB)*100 =44%
Rahul said:
1 decade ago
Let us supoose l=10, b=10 area=l*b=10*10=100
n aftr inc l=12 , b=12 area=l*b=12*12=144
144-100=44%ans
n aftr inc l=12 , b=12 area=l*b=12*12=144
144-100=44%ans
Deepi said:
1 decade ago
Hi guys i have a easy step to this kind of sum,
if any one side is increased a% mean what is the increment of area can be calculated by the following formula
=2a+(a^2/100)
similarly if a% decrease means area also decreased by
=2a-(a^2/100)
In the above sum side is increased 20 while applying it in the formula
=2*20+(20*20/100)
=40+4
=44
if any one side is increased a% mean what is the increment of area can be calculated by the following formula
=2a+(a^2/100)
similarly if a% decrease means area also decreased by
=2a-(a^2/100)
In the above sum side is increased 20 while applying it in the formula
=2*20+(20*20/100)
=40+4
=44
G@ni said:
1 decade ago
I had a small and sweet solution for this problem.
The formula for % increase is x+y+xy/100.
And for %decrease is x+y-xy/100.
Now x=20.
y=20.
Therefore substituting in the above formula .
20+20+(20*20/100)=40+(400/100).
=40+4.
=44%.
The formula for % increase is x+y+xy/100.
And for %decrease is x+y-xy/100.
Now x=20.
y=20.
Therefore substituting in the above formula .
20+20+(20*20/100)=40+(400/100).
=40+4.
=44%.
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.
.
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.
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.
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 %.
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%.
Mani said:
1 decade ago
From where have we got new length and new breadth.
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