Hello,

Let the cost price of the goat be 'X'

The selling price at loss 10% = Rs. (X*(100-loss%)/100)= Rs. ((90*X)/100)

The selling price at gain 121/2% = Rs. (X*(100+gain%)/100) = Rs. ((160.5*X)/100

Now

((160.5*X)/100)-  ((90*X)/100) =9

that implies ((70.5*X/100)=9

the implies 70.5*X=900

That implies X=900/70.5= 12.76

So the cost price of the Goat is Rs. 12.76