A man sells two articles, each for $Rs.\,640.$ He earns $20 \%$ profit on the first, and $40 \%$ profit on the second. Find his overall percent profit.

In a certain store, the profit is $320 \%$ of the cost. If the cost increases by $25 \%$ but the selling price remains constant, approximately what percentage of the selling price is the profit?

A cash payment that will settle a bill for $250$ chairs at $Rs.\,50$ per chair less $20 \%$ and $15 \%$ with a further discount of $5 \%$ on cash payment is (in $Rs.$)

A dishonest dealer use a scale of $90\, cm$ instead of a metre scale and claims to sell at cost price. His profit is in $\%$

$'A'$ bought a certain quantity of oranges at total cost of $Rs.\, 1200 /-$ He sold $1 / 3^{\text {rd }}$ of those oranges at $20 \%$ loss. If $A$ earns an overall profit of $10 \%,$ at what percent profit did $A$ sell the rest of the oranges?

In these questions, two equations mabered $I$ and $II$ are given. You have to solve both the equations and mark the appropriate option..

$I$. $6 x^{2}+19 x+15=0$

$II$.$3 y^{2}+11 y+10=0$