Question

Please answer the fifth one

Answer 1

2(l+b)=240
l+b= 120
let take l as X and b as y
90x/100 +120y/100 =120
9x/10 +12y /10 =120
9x+12y=1200
[x+y = 120 , x=120-y ]
9(120-y) +12y =1200
1080 -9y +12y =1200
3y =1200-1080=120
y=120/3=40=breadth
x= 120-40 =80= length