Aptitude - Area - Discussion
Discussion Forum : Area - General Questions (Q.No. 12)
12.
The length of a rectangle is halved, while its breadth is tripled. What is the percentage change in area?
Answer: Option
Explanation:
Let original length = x and original breadth = y.
Original area = xy.
| New length = | x | . |
| 2 |
New breadth = 3y.
| New area = |  |
x | x 3y |  |
= | 3 | xy. |
| 2 | 2 |
 Increase % = |
|
1 | xy x | 1 | x 100 | % |
= 50%. |
| 2 | xy |
Discussion:
25 comments Page 1 of 3.
Kanmani said:
1 decade ago
Increase% = (new area-original)/original.
Sri said:
1 decade ago
Please explain in detail.
Isn't it.
New area/original area = (3/2xy) /xy.
Isn't it.
New area/original area = (3/2xy) /xy.
Arun said:
1 decade ago
Hey sri wat kanmani told is right
see new area =3/2xy
orginal area=xy
so (3/2xy-xy)/xy=.50%(i.e)50%
see new area =3/2xy
orginal area=xy
so (3/2xy-xy)/xy=.50%(i.e)50%
Adilakshmi said:
1 decade ago
Please explain clearly what is the formula used.
Sri said:
1 decade ago
Thanks kanmani for your good explanation.
Xyz said:
1 decade ago
@adilakshmi
Please see kanmani explanation
First we take
orginal length=x, new lenth=half of the orginal length
orginal breath=y, ie)l=x/2,new breath=breath is tribled
orginal area=length*breath, ie)b=3y
=xy , new area=x/2*3y=3xy/2
increase %=((new area-orginalarea)/orginal area)*100
=(3xy/2-xy)/xy [here 3/2=1.5]
=(1.5xy-xy)/xy
=(0.5xy/xy)
=0.5*100 [use 100 because to find the PERCENTAGE]
=50%
NOW ARE U CLEAR ADI?
Please see kanmani explanation
First we take
orginal length=x, new lenth=half of the orginal length
orginal breath=y, ie)l=x/2,new breath=breath is tribled
orginal area=length*breath, ie)b=3y
=xy , new area=x/2*3y=3xy/2
increase %=((new area-orginalarea)/orginal area)*100
=(3xy/2-xy)/xy [here 3/2=1.5]
=(1.5xy-xy)/xy
=(0.5xy/xy)
=0.5*100 [use 100 because to find the PERCENTAGE]
=50%
NOW ARE U CLEAR ADI?
Sundar said:
1 decade ago
We can solve this question by simply taking an example. Let me explain.
Assume a rectangle, lxb = 4x2 and area = 8 (4*2).
New Length (after halved 4/2) = 2
New Breadth (after tripled 2*3) = 6
New area of rectangle = 2x6 = 12.
Change in area = 12 - 8 = 4.
Now % of change is 4/8*100 = 50%.
Hope this will help you. Have a nice day!
Assume a rectangle, lxb = 4x2 and area = 8 (4*2).
New Length (after halved 4/2) = 2
New Breadth (after tripled 2*3) = 6
New area of rectangle = 2x6 = 12.
Change in area = 12 - 8 = 4.
Now % of change is 4/8*100 = 50%.
Hope this will help you. Have a nice day!
Anshu said:
1 decade ago
ORIGINAL
LENGTH = X
BREADTH = Y
AREA = XY
----------------------------
LENGHT = 0.5X
BREADTH = 3Y
AREA = 1.5XY
THERE WAS INCREASE OF O.5 XY
0.5XY / XY * 1OO = 50%
SHORT AND CRISP METHOD
LENGTH = X
BREADTH = Y
AREA = XY
----------------------------
LENGHT = 0.5X
BREADTH = 3Y
AREA = 1.5XY
THERE WAS INCREASE OF O.5 XY
0.5XY / XY * 1OO = 50%
SHORT AND CRISP METHOD
Ketan Mehta said:
1 decade ago
@Anshu
Nice Dude!
Nice Dude!
Abc said:
1 decade ago
How to know the area increasing or decreasing ?
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