$X$ sells an item to $Y$ at a profit of $20\%$ and $Y$ sells it to $Z$ at a loss of $15\%$. If $Z$ pays $₹1224$ for it, what is the price at which $X$ bought the item?

Arman takes a loan of $₹480000$ to buy a used truck at the rate of $11\%$. He clears the loan by paying $₹691200$. After how many years did he clear the loan?

A sum becomes $1\frac{16}{25}$ itself in $x$ years at a $x\%$ rate of interest per annum. Find the time and rate of interest.

Determine the simple interest rate applied to a principal over $25$ years, if the total interest paid equals the borrowed principal.

A car takes $15$ hours to cover at a distance, if it travels at a speed of $50 kmph$, what should be its speed to cover the same distance in $10$ hours?

Mohan travels in an aeroplane at a distance of $1200 km$ for the first half of the distance, the plane flies at a speed of $900 kmph$ and to the rest of the distance, it flies at a speed of $750 kmph$. How long does the trip take?