If a radio is purchased for $Rs. 490$ and sold for $Rs. 465.50$,find the $\text{loss} \%$. (in $\%$)

Due to a $20\%$ rise in the price of sugar,a bachelor is able to buy $1.5\, kg$ less for $Rs.\, 135$. What is the increased price of sugar per $kg$ in $Rs.$?

$X$ sells two articles for $Rs. 4,000$ each with no loss and no gain in the transaction. If one was sold at a gain of $25\%$, the other is sold at a loss of ........$\%$.

The cost price of an article is $64 \%$ of the marked price. The gain percentage after allowing a discount of $12 \%$ on the marked price is........$\%$

$A$ garment company declared $15\%$ discount for wholesale buyers. Mr. Ashish bought garments from the company for $Rs. 25000$ after getting the discount. He fixed the selling price of the garments in such a way that he earned a profit of $8\%$ on the original company price. What is the approximate total selling price? (in $Rs.$)

Nutan pays $Rs. 2140$ for $3$ calculators and $4$ pens,while she pays $Rs. 1355$ for $1$ additional calculator and $5$ pens. What is the cost of a calculator in $Rs.$?