pls answer my question

Answer :

Given  : He bought 12 kg of fish at Rs 140 per kg.
So,
Cost of total  fish bought by Akhil  = 12 $\times$ 140 = Rs . 1680 
And
He spent Rs 120 to take this to the shop .
So,
Total money spent by Akhil = 1680 + 120  = Rs . 1800

And also given : 4 kg of fish were spoilt and he sold the rest at Rs 180 per kg. 

Akhil sold his fish =  180  $\times$  8   =  1440 



Now, total CP > Total SP
now, there occurs a loss.
Loss = CP  -  SP = 1800 - 1440 = Rs 360
$$\begin{gathered} \mathrm{Loss}\%=\frac{\mathrm{Loss}}{\mathrm{CP}}\times 100 \\ =\frac{360}{1800}\times 100 \\ =20 \end{gathered}$$