if the length of a rectangle is increased by 30% and the width is decreased by 20%, then the area is increased by...
(a) 10% (b) 5% (c) 4% (d) 20% (e) 25%

• ans=4%
  
  area=length* width
  length increased by 30 %
  length=1.3 length
  
  and width decreased by 20%
  width=0.8 width
  
  now ,area = (1.3 * 0.8)length* width
  =0.04 area
  so 4% area increased...
  
• 12 years agoHelpfull: Yes(16) No(2)
• assume length=100 and breadth=100
  lxb=10000
  l increased by 30%=100+30=130
  b reduced by 20%=100-20=80
  lxb=10400
  before area=10000
  after area=10400
  therefore 4% increase is answer
• 12 years agoHelpfull: Yes(9) No(0)
• (c) 4%
  
  If initial length and breadth are l and b respectively, then
  
  Initial area = lb
  Final area= 1.3l*0.8b = 1.04 lb
  change in area = 0.04 lb
  
  % increase = 100*0.04lb/lb = 4%
• 12 years agoHelpfull: Yes(5) No(2)
• Shortcut method
  
  30% increase means= 130%
  20% decrease means = 80%
  
  therefore, 130* 80/100=104%
  
  100 is a base , so it is 4% increase
  
  
• 11 years agoHelpfull: Yes(3) No(0)
• ans=4%
  
  area=length* width
  length increased by 30 %
  length=1.3 length
  
  and width decreased by 20%
  width=0.8 width
  
  now ,area = (1.3 * 0.8)length* width
  =0.04 area
  so 4% area increased...
• 12 years agoHelpfull: Yes(1) No(1)
• Answer=area increased by 4%
• 12 years agoHelpfull: Yes(1) No(2)
• ANS IS :4%
  TAKE DEFAULT 100%
  LENGTH INCREASED 30 % =130
  WIDTH DECREASED 20% =80
  AREA IS INCREASED BY, AREA=LENGTH*WIDTH/100
  130+80/100=104
  104-100=4
  AREA IS INCREASED BY 4%
  
• 9 years agoHelpfull: Yes(1) No(1)
• 30-20-(30*20)/100=4
• 9 years agoHelpfull: Yes(1) No(0)
• 4%
  Take an easy example to solve
  let original length=10 and width=7
  original area=10*7=70
  
  after 30% inc. of length,l becomes 13
  and after 20% dec. of width,width becomes 5.6
  Area=new length x new breadth=13 * 5.6=72.8
  
  Therefore % increase=(72.8/70)*100= 104 %
  
  This clearly states a 4% increase
• 9 years agoHelpfull: Yes(0) No(0)
• the correct option is (C)=4%
• 9 years agoHelpfull: Yes(0) No(0)
• (130*80)/100-100=4 %
• 9 years agoHelpfull: Yes(0) No(0)
• L1=100,b1=100
  l2=130,b2=80
  increase in Area= l2b2-l1b1
  =(130*80)-(100*100)
  =400=4%
  ans is c
• 9 years agoHelpfull: Yes(0) No(0)
• LENGTH INCREASED = +30%
  WIDTH DECREASED = -20%
  
  SO TOTAL CHANGE IN AREA = +30 - 20 - ((30*20)/100) % = +4%
  SO THE AREA IS INCREASED BY 4%
  
• 9 years agoHelpfull: Yes(0) No(0)
• ans 4 % as (130*80-100*100)/100*100 *100=(10400-10000)/10000 *100=4% ANS
• 9 years agoHelpfull: Yes(0) No(0)
• let length and width be x=100, y=100
  30% increase in length means x=130
  20% decrease in width means y=80
  130*80=10400
  therefore increase in area= 400*100/10000=4%
• 9 years agoHelpfull: Yes(0) No(0)
• let len=20 wid=10 and area=200
  now len=26, wid=8
  area=26*8=208
  
  200==>208
  100==>104
  
  area increased by 4%
• 8 years agoHelpfull: Yes(0) No(0)