If the width of a rectangle is increased by 10% and the length is decr

Question

If the width of a rectangle is increased by 10% and the length is decreased by 20%, by what percent does the area decrease?

A. 5 
B. 12
C. 15 
D. 20
E. 21

Archit3110 · Answer

inital w = 10 new = 11
intial L = 20 . new = 16
% change in area = 200-176/200 ; 12%
IMO B

Kinshook · Answer

New width = 1.1 width
New length = .8 length
New Area = 1.1 * .8 area
=.88 area
=(1-12%) area

IMO B

eakabuah · Answer

Aold=WL
Anew=1.1W*0.8L=0.88WL
Percenttage change 
=((WL-0.88WL)/WL)*100%
=12%

Hence B.

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CareerGeek · Answer

Let the initial width = 10.
Final width = 10% more = 11

Let the initial length = 10
Final length = 20% less = 8

Initial area = length*width = 10*10 = 100
Final area = length*width = 11*8 = 88

So, % decrease = 12

IMO Option B

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QuantMadeEasy · Answer

Lets say area is 100
width increased by 10%, area will be 110
and then length decreased by 20%, area becomes 110*0.80 = 88

Area decreased by 12% 
B is correct

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