Sardar singh bought $200$ dozen oranges at $Rs.\,10$ a dozen. He spent ₹500 on transportation. He sold them at $Rs.\,1$ each. What was his profit or loss percent?

A cab driver makes a profit of $20 \%$ on every trip when he carries $3$ passengers and the price of petrol is $Rs.\,30$ a litre. Find the percentage profit for the same journey if he goes with four passengers per trip and the price of petrol reduces to $Rs.\, 24$ a litre? (in $\%$)

(Assume that revenue per passenger is the same in both the cases.)

Nisha bought a number of oranges at $2$ for a rupee and an equal number at $3$ for a rupee. To make a profit of $20 \%$ she should sell a dozen for (in $Rs.$)

With a $5 \%$ discount on the cost of sugar, a buyer could purchase $2\, kg$ more sugar for $Rs.$ $608 .$ Selling price of sugar is? (in $Rs$)

When a plot was sold for $Rs$ $18700,$ the owner lost $15 \% .$ At what price must the plot be sold in order to gain $15 \% ?$

A man sells a scooter to his friend at $10 \%$ loss. If the friend sells it for $RS.\, 4000$ and gains $20\%,$ find out the original cost price of the scooter. (in $Rs.$)