Answer:
SP of 8 articles =Rs 7360
Profit=15%
Now,
SP of each article =7360/8= Rs920
Wkt,
SP=CP+profit (let CP=x)
920=x+15%of CP
920=x+15÷100× x
920=x+15x÷100
920=(100x+15x)÷100
920=115x÷100
92000=115x
92000÷115=x
Therefore, x=Rs 800
CP=800(i.e Cost price of one article)
Again,
SP of 13 articles=Rs 11440
SP of 1 article=11440÷13=Rs 880
Since,SP>CP
Profit!
Profit=SP-CP
=880-800
=Rs 80
Profit%=profit÷CP×100%
=80÷800×100
=10%
Im not sure if this is correct but x=4 double roots
Area=l*b=l*(l-2)=80(given)
so, l^2 - 2l =80
l^2 - 2l - 80=0
l=10 or -8
l=10,b=10-2=8
perimeter=2(l+b)=2(18)=36
