The population of Mumbai increases by $5 \%$ per annum. Its population was $100000$ in $2004$. What was its population after $3$ years?

An automobile financier claims to be lending money at simple interest,but he includes the interest every six months for calculating the principal. If he is charging an interest of $10 \%$ per annum,the effective rate of interest (in $\%$) becomes:

Simple interest on a certain sum is $\frac{16}{25}$ of the sum. If the rate per cent and time (in years) are equal,then the rate per cent is:

What time (in years) is taken by a sum of $Rs. 7000$ to become $Rs. 10500$ at the rate of $5 \%$ per annum simple interest?

Prakash lends a part of ₹ $20,000$ at $8 \%$ simple interest and the remaining at $\frac{4}{3} \%$ simple interest. His total income after a year was ₹ $800$. Find the sum (in ₹) lent at $8 \%$ interest.

Peter invested an amount of ₹ $12,000$ at the rate of $10 \%$ $p.a.$ simple interest and another amount at the rate of $20 \%$ $p.a.$ simple interest. The total interest earned at the end of one year on the total amount invested became $14 \%$ $p.a.$ Find the total amount (in ₹) invested.