Instead of dividing $391$ cookies among $3$ children $A, B, C$ in the ratio $\frac{1}{5}: \frac{1}{4}: \frac{1}{8}$,they were divided in the ratio $5: 4: 8$. Who gains the most and how many?

$A$ manufacturer undertakes to supply $2000$ pieces of a particular component at $Rs. 25$ per piece. According to his estimates,even if $5\%$ fail to pass the quality tests,he will make a profit of $25\%$. However,as it turned out,$50\%$ of the components were rejected. What is the loss to the manufacturer? (in $Rs.$)

Aditya sold a $TV$ to Sanjay at $12 \%$ more than the $CP.$ If Sanjay paid $Rs. 17696$ for that $TV,$ then what was the original price $(CP)$ of the $TV$ in $Rs.$?

Aditya purchased a book with a $20 \%$ discount on the marked price. How much $Rs.$ did he pay if the marked price of the book was $Rs. 500$?

$A$ person sells taperecorders at $Rs. 1134$ each after giving a discount of $19 \%$ on the marked price. Had he not given the discount,he would have earned a profit of $40 \%$ on the cost price. The cost price of each taperecorder is (in $Rs.$)

$A$ shopkeeper sold chairs at $Rs. 2139$ each after giving a $7 \%$ discount on the labelled price. Had he not given the discount, he would have earned a profit of $15 \%$ on the cost price. What was the cost price of each chair? (in $Rs.$)