An article is marked $40 \%$ above the cost price and a discount of $30 \%$ is allowed. What is the gain or loss percentage?

The true discount on a bill of $Rs. 2550$ due after $3$ months is $Rs. 50$. Find the banker's discount (in $Rs.$).

The difference between the simple interest and the true discount on a certain sum of money for $2$ years at $15 \%$ per annum at simple interest is $Rs. 45$. Find the sum (in $Rs.$).

If the compound interest on a certain sum of money for $2 \text{ years}$ at $4 \%$ per annum is $Rs. 45.90$,the true discount on the same amount of money due $2 \text{ years}$ hence at $4 \%$ per annum simple interest is (in $Rs.$):

The true discount on a certain bill due for nine months at $4 \%$ simple interest is $Rs.\, 150$. Find the amount of the bill (in $Rs.$).

$A$ owes $B$ $Rs. 1350$ due in $3$ months and $B$ owes $A$ $Rs. 1078$ due in $5$ months. If they agree to settle their account right now at $5\%$ $p.a.$ simple interest,how much should $A$ pay to $B$ (in $Rs.$)?