Aptitude - Area - Discussion

3. 

The ratio between the perimeter and the breadth of a rectangle is 5 : 1. If the area of the rectangle is 216 sq. cm, what is the length of the rectangle?

[A]. 16 cm
[B]. 18 cm
[C]. 24 cm
[D]. Data inadequate
[E]. None of these

Answer: Option B

Explanation:

2(l + b) = 5
b 1

2l + 2b = 5b

3b = 2l

b = 2 l
3

Then, Area = 216 cm2

l x b = 216

l x 2 l = 216
3

l2 = 324

l = 18 cm.


P.Bharathi said: (Oct 2, 2010)  
I have done like below :

Perimeter=2(l+b),

5x=2(l+x)=2l+2x => l=3x/2,

Area = 3x/2*x = 216=> I got the value for x is 12 which is the length.

Is it correct ah?

Sankar said: (Feb 19, 2011)  
No its wrong. Value is given in ratio.

Shahid said: (May 19, 2011)  
@Bharathi ..your answer is absolutely right.
There is no error in it.

Muthulakshmi said: (Sep 8, 2011)  
@Bharathi

your ans is correct .12 is not the length it is the value of breath.
see your explanation.
perimeter=2(l+b)
ratio b/w perimeter and breathis 5:1
5x=2(l+x)=2l+2x=>"l=3x/2",
area =3x*x/2=21=>x=12 which is not the value of length
substitute the value of "x" in the equation L=3x/2=(3*12)/2=18

ARE U CLEAR ?

Engr. Md. Easir Arafat said: (Nov 23, 2014)  
Let the breadth to be x and the length to be y.

Hence, perimeter becomes 5x.

Now, 5x = 2(x+y).
Or, 3x = 2y -----------1.

Again, x*y = 216.
Or, x = 648/y ----------2.

Putting the value of x in eq. no. 1, we get,

648/y = 2y.
Or (2y*y) = 648.
Or y = Sqrt 324 = 18 cm.

Sajid said: (May 14, 2015)  
2(l+b)/b.

Please explain why divided b?

Sravani said: (Jul 12, 2015)  
Ratio is given in terms of perimeter and breath i.e, 5:1.

Let length be 'l' and breadth be 'b'.

Perimeter = 2 (l+b).

Breadth = b.

So (perimeter/breadth) = 5:1.

(2(l+b)/b) = 5:1.

I think you got?

Ujjwal Mondal said: (Oct 16, 2016)  
I cannot understand it. Please solve it by a simple rule.

Kartik said: (Oct 21, 2016)  
How can 2 (l + b)/b we let as = 5/1?

Shona said: (Jan 7, 2017)  
Please explain in simple method.

Ramana said: (Feb 14, 2017)  
Not understanding. Please explain me.

Abi said: (Jul 18, 2017)  
2(5x+x)=216,
12x=216,
x=18.

Karan Khitan said: (Feb 8, 2018)  
Suppose 5x nd 1x.

Perimeter = 2 (L*b).
2(5x+1x)=216,
2(6x)=216,
12x=216,
X=18cm.

Tanweer said: (Aug 8, 2018)  
Simply;

2(l+b)=216.
2(5+2)=2016.
12=216.
Ans = 18.

Mahi said: (Dec 1, 2018)  
2(5+1)216.
= 12/216
= 18

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