A person sells $36$ oranges per $Rs.\, 1$ and makes a loss of $4 \% .$ Find how many oranges per $Rs$ to be sold to have a gain of $8 \% ?$

A discount dealer professes to sell his goods at cost price but uses a weight of $960\, gms$ instead of a $Kg$ weight. Find his gain $\% ?$

A man purchased some eggs at $3$ for $Rs.\, 5$ and sold them at $5$ for $Rs.\, 12 .$ Thus, he gained $Rs.\, 143$ in all. The number of eggs he bought is

Present age of Bob is equal to Abby's age $8\, years$ ago. Four years hence, the respective ratio between Bob's age and Abby's age will be $4: 5$ at that time. What is Bob's present age? (in $years$)

A fruit seller sells $\frac{3}{5}$ th part of fruit at a profit of $10 \%$ and remaining at a loss of $5 \% .$ If the total profit is $Rs.\, 1500$ then what is the total cost price of fruit in $Rs.$?