Aptitude  Area  Discussion
Discussion Forum : Area  General Questions (Q.No. 7)
7.
A towel, when bleached, was found to have lost 20% of its length and 10% of its breadth. The percentage of decrease in area is:
Answer: Option
Explanation:
Let original length = x and original breadth = y.
Decrease in area 





Decrease % =  7  xy x  1  x 100  %  = 28%.  
25  xy 
Discussion:
26 comments Page 1 of 3.
Akil said:
2 years ago
It is simple.
L(0.80)*B(0.90).
= LB(0.72).
So, 100  72= 28% loss.
L(0.80)*B(0.90).
= LB(0.72).
So, 100  72= 28% loss.
(12)
Kpkakadiya said:
2 years ago
Let L=10, B=10.
area = 10 * 10 = 100.
Now after bleached,
L = 80% of L
= 80% of 10,
= 8.
B= 90% of B,
= 90% of 10.
= 9.
Area = 8*9 = 72.
Decrease of area in % = (100  72 * 100)/100.
= 28.
area = 10 * 10 = 100.
Now after bleached,
L = 80% of L
= 80% of 10,
= 8.
B= 90% of B,
= 90% of 10.
= 9.
Area = 8*9 = 72.
Decrease of area in % = (100  72 * 100)/100.
= 28.
(2)
D.Mukul Raj said:
3 years ago
According to me, the solution is;
Suppose initial size = 120(L) x 110(B) = 13200.
and,
The towel shrunk down to 100(L) x 100(B) =10000.
so difference should be 1320010000= 3200.
And if I divide 3200 by 13200 why am i getting the decreased area to be ( 8/33 ) ie 24.24242%.
Am I right? Please anyone clarify.
Suppose initial size = 120(L) x 110(B) = 13200.
and,
The towel shrunk down to 100(L) x 100(B) =10000.
so difference should be 1320010000= 3200.
And if I divide 3200 by 13200 why am i getting the decreased area to be ( 8/33 ) ie 24.24242%.
Am I right? Please anyone clarify.
(1)
Deepak virat said:
4 years ago
80*90/100 = 72.
As we see 28 is reduced so we can say that the percentage decrease is 28%.
As we see 28 is reduced so we can say that the percentage decrease is 28%.
(1)
OMARFARUK said:
4 years ago
Main formula +p+q+(pq/100).
2010+(20* 10 / 100) = 28%.
(ve) indicates area decrease.
2010+(20* 10 / 100) = 28%.
(ve) indicates area decrease.
Pinku said:
5 years ago
x=a*80/100
y=b*90/100
Area=x*y=80*a*90*b/100*100=72/100(a*b)
decreased area=total area(ab)72ab/100
=ab72ab/100
=10072(ab/100)
=28/100(ab)
= 0 .28ab or 28ab%.
Decreased area by 28%.
y=b*90/100
Area=x*y=80*a*90*b/100*100=72/100(a*b)
decreased area=total area(ab)72ab/100
=ab72ab/100
=10072(ab/100)
=28/100(ab)
= 0 .28ab or 28ab%.
Decreased area by 28%.
Jatin said:
7 years ago
2010+20*10/100 = 28%.
Dhanraj said:
8 years ago
How 7/25 came there? Explain it.
Sreelu said:
8 years ago
There is another simple method.
Let's assume L = 10 and B = 10.
Then area will be 100 (L * B).
When L lost 20% it gets the value 8.
Like that, B lost 10% it gets the value of 9.
So, the new area is 72 i.e (8 * 9).
Then % decrease = 100  72 = 28.
Let's assume L = 10 and B = 10.
Then area will be 100 (L * B).
When L lost 20% it gets the value 8.
Like that, B lost 10% it gets the value of 9.
So, the new area is 72 i.e (8 * 9).
Then % decrease = 100  72 = 28.
(1)
Islam Ansari said:
8 years ago
xy  18/25xy.
= 7/25xy.
How?
= 7/25xy.
How?
Post your comments here:
Quick links
Quantitative Aptitude
Verbal (English)
Reasoning
Programming
Interview
Placement Papers