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 $\%$?

If the discount of $10 \%$ is given on the marked price of a radio, the gain is $20 \%$. If the discount is increased to $20 \%,$ the gain is......$\%$

A fruit-seller buys some oranges and by selling $40 \%$ of them he fealises the cost price of all the oranges. As the oranges being to grow over-ripe, he reduces the price and sells $80 \%$ of the remaining oranges at half the previous rate of profit. The rest of the oranges being rotten are thrown away. The overall percentage of profit is

By selling an article for $Rs.\, 450,$ a man loses $10 \% .$ The gain or loss percent if he sells it for $Rs.\, 540$ is

When a plot was sold for $Rs$ $18700,$ the owner lost $15 \% .$ At what price must the plot be sold in order to gain $15 \% ?$

A person sold a radio at a loss of $5 \% .$ Had he sold it for $Rs\, 210$ more, he would have gained $25 \%$. For what value should he sell it in order to gain $35 \% ?$