The cost price of $20$ articles is the same as the selling price of $x$ articles. If the profit is $25 \%$,then the value of $x$ is:

Suresh purchased a $TV$ set for $Rs. 11250$. He spent $Rs. 800$ on installation and $Rs. 150$ on transportation. At what price should it be sold so that the profit earned would be $15\%$,if no discount was offered? (in $Rs.$)

Nutan bought $30$ dozens of oranges for her juice stall in the school fair. She paid $Rs. 8$ per dozen of oranges. She also had to pay $Rs. 500$ as the stall fee to the school authorities. She calculated that each glass of juice would need $3$ oranges. How much should she charge per glass of juice so as to make $20 \%$ profit in $Rs$?

By selling $80$ ball pens for $₹ 140$,a retailer loses $30 \%$. How many ball pens should he sell for $₹ 104$ so as to make a profit of $30 \% ?$

$A$ discount series of $10 \%$,$20 \%$,and $40 \%$ is equal to a single discount of.......$\%$

If the selling price of $50$ articles is equal to the cost price of $40$ articles,then the loss or gain percent is: