Find $SP$ when $CP = Rs. 80.40$ and $\text{loss} = 5\%$.

Ram purchased a computer set for $Rs. 12500$ and spent $Rs. 300$ on transportation and $Rs. 800$ on installation. At what price should he sell it to earn an overall profit of $15\%$? (in $Rs.$)

$A$ shopkeeper purchased a chair marked at $₹ 600$ at two successive discounts of $15 \%$ and $20 \%$. He spent $₹ 28$ on transportation and sold the chair for $₹ 545$. His gain percent was: (in $\%$)

Sasha goes to a shop to buy a sofa set and a center table. She bargains for a $10 \%$ discount on the center table and a $25 \%$ discount on the sofa set. However,the manager,by mistake,interchanged the discount percentage figures while making the bill and Sasha paid accordingly. When compared to what she should have paid for her purchases,what percentage did Sasha pay extra,given that the center table costs $40 \%$ as much as the sofa set (in $\%$)?

$A$ man sold his two horses for $Rs. 770$ each. On one he gained $10\%$ and on the other he lost $10\%$. The average gain or loss percentage is:

$A$ man sells an article at $5 \%$ above its cost price. If he had bought it at $5 \%$ less than what he had paid for it and sold it at $Rs. 2$ less,he would have gained $10 \%$. The cost price of the article is (in $Rs.$)