Given, for the first
article
S.P=Rs1,890
Profit =12.5 %
Now, with this S.P. and for Profit % =S.P.−C.P.C.P.×100=12.5 %
=>1,890−C.P.C.P.×100=12.5
=>1,890−C.P.=0.125C.P.
1.125C.P.=1,890
=>C.P.=Rs1,680
And for another TV,
S.P=Rs2,400
Profit =20 %
So, Profit % =S.P.−C.P.C.P.×100=20
=>2,400−C.P.C.P×100=20
=>2,400−C.P.=0.20C.P.
=>1.2C.P=2,400
=>C.P.=Rs2,000
Now Total S.P. =Rs1,890+Rs2,400+Rs1,135=Rs5,425
And Total Loss % =TotalC.P.−TotalS.P.TotalC.P.×100=258 %
=>TotalC.P.−5,425TotalC.P.×100=258
on solving we get
Total C.P =Rs5,600
Hence, C.P. of third article = Rs5,600−Rs1,680−Rs2,000=Rs1,920