An electric pump was sold at a profit of $15 \%$. Had it been sold for $Rs. 600$, the profit would have been $20 \%$. What was the former selling price in $Rs.$?

In these questions,two equations numbered $I$ and $II$ are given. You have to solve both the equations and mark the appropriate option.
$I$. $6x^2 + 19x + 15 = 0$
$II$. $3y^2 + 11y + 10 = 0$

$10 \%$ discount and then $20 \%$ discount in succession is equivalent to a total discount of $... \%$.

Successive discounts of $10 \%$,$20 \%$ and $50 \%$ will be equivalent to a single discount of .......... $\%$

$A$ sells an article to $B$ at a gain of $20 \%$,$B$ sells it to $C$ at a gain of $10 \%$,and $C$ sells it to $D$ at a gain of $12 \frac{1}{2} \%$. If $D$ pays $Rs. 29.70$,what was the cost price for $A$? (in $Rs.$)

$A$ man gains $20 \%$ by selling an article for a certain price. If he sells it at double the price,what will be the percentage of profit (in $\%$)?