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 $Rs.$?

Three successive discounts of $10 \%$,$12 \%$,and $15 \%$ are equivalent to a single discount of what percentage (in $\%$)?

Mr. Kapur purchased two toy cycles for $Rs. 750$ each. He sold these cycles,gaining $6 \%$ on one and losing $4 \%$ on the other. The gain or loss percent in the whole transaction is

$A$ man had a certain amount with him. He spent $20\%$ of that to buy an article and $5\%$ of the remaining on transport. Then he gifted $Rs. 120$. If he is left with $Rs. 1,400$,the amount he spent on transport is (in $Rs.$)

$A$ man bought $4$ dozen eggs at $Rs. 24$ per dozen and $2$ dozen eggs at $Rs. 32$ per dozen. To gain $20\%$ on the whole,he should sell the eggs at what price in $Rs.$ per dozen?

$A$ shopkeeper allows a discount of $12.5 \%$ on the marked price of a certain article and makes a profit of $20 \%$. If the article costs the shopkeeper $Rs. 210$,then the marked price of the article will be (in $Rs.$)