A person earns $15 \%$ on investment but loses $10 \%$ on another investment. If the ratio of the two investments be $3: 5,$ what is the gain or loss on the two investments taken together in $\%$?

A shopkeeper sold an article offering discount of $24 \%$ and earn a profit of $23.5 \% .$ What would have been the percentage of profit earned if no discount has been offered?

$A, B, C$ are partners in a business. During a particular $year,$ A received one third of the profit, $B$ received $\frac{1}{4}$ of the profit and $C$ received the remaining $Rs.\, 5000$ How much amount of money did A receive? (in $Rs.$)

Mohit purchased $40\, kg$ of wheat at $Rs.\,12 .50$ per $kg$ and $25\, kg$ of wheat at $Rs.\,15.10$ per $kg.$ He mixed the two qualities of wheat for selling. At what rate should it be sold to gain $10 \% ?$ (in $Rs.)$

Vijay sold a watch at a gain of $5 \%$. Had he sold it for $Rs.\, 72$ more, he would have gained $13 \%$. Find out the cost price of the watch. (in $Rs.$)

A trader sells his table at a profit of $15 \%$ and the chair at a loss of $7 \frac{1}{2} \%,$ but on the whole he gains $Rs.\, 50 .$ If he sells the table at a loss of $7 \frac{1}{2} \%,$ and chair at a profit of $15 \%,$ then he neither gains nor loses. Find the cost price of the table