Nutan pays $Rs.\, 2140$ for $3$ calculator and $4$ Pen while he pay $Rs.\, 1355$ for an additional calculator and $5$ Pen. Then what he paid for Calculator only in $RS.$?

An article is marked for sale at $Rs.$ $504 .$ The shopkeeper gives a discount of $5 \%$ on the sale price and still earns a profit of $20 \% .$ What could be the purchase price of the article? (in $Rs.$)

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

A vendor started selling vegetables at $Rs. 10$ per $k g,$ but couldn't find buyers at this rate. So, he reduced the price to $8.10 / kg ,$ but uses a faulty weight of $900\, g$ for $1\, kg .$ Find the percent change in the actual price or loss.

A trader marked the selling price of an article at $10 \%$ above the cost price. At the time of selling, he allows certain discount and suffers a loss of $1 \% .$ He allowed a discount of $\%$

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