Reena took a loan of ₹ $1,200$ with simple interest for as many years as the rate of interest. If she paid ₹ $432$ as interest at the end of the loan period,what was the rate of interest?

Divide $Rs. 4758$ into three parts such that their amounts after $2, 3,$ and $4$ years respectively are equal,given the rate of interest is $5 \%$ per annum. Find the amount of the $1^{\text{st}}$ part (in $Rs.$).

Mr. Irani borrowed a sum of ₹ $10000$ from a finance company for $6$ years at $8 \%$ per annum. The amount (in ₹) returned by Mr. Irani to the finance company is:

An investor invested his savings in the stock market. The value of his investments increased by $12 \%$ and $9 \%$ in the first year and the second year respectively. If the value of his investments after two years became ₹ $97,664$,then how much had he invested (in ₹)?

Gaurav borrowed $Rs. 800$ at $6 \%$ and Naresh borrowed $Rs. 600$ at $10 \%$. After how much time will they both have equal debts?

Dalajit lent ₹ $10800$ to Jaabir for $3$ $years$ and ₹ $7500$ to Kabir for $2$ $years$ on simple interest and received ₹ $1422$ in all from both of them as interest. The rate of interest (in $\%$) per annum is