Bidyut Guha Thakurta and Amitava Mitra Solutions for Exercise 1: EXERCISE 3

A person invests $₹2,50,000$ to start a business. He makes a profit at a rate of $5\%$ and $10\%$ respectively. How much profit does he make?

The price of a machine decreases from its previous years price at a rate of $10\%. 3$ years ago its price was $₹8,000$. Find the present price of the machine.

The price of a machine decreases at a rate of $x\%$ from its previous year's value. If the present price is $₹P$, the price of the machine two years ago is

The value of a land increases every year at a uniform rate. After 5 years the value of land becomes double its present value. After how many years will its price be 8 times the present value.

The weight of a person is 40 kg. He decides to reduce his weight at a rate of 5% every year. Find his weight after 3 years.

The present price of a machine is $₹20,000$. Find the annual depreciation rate so that its price becomes $₹14,580$ after 3 years.

The present population of a city is $P$ and the rate of growth of the population is $r\%$ per annum. The population of the city after$n$ years will be _____${\left(1+\frac{r}{100}\right)}^n$.

The present price of a machine is $P$ and the rate of depreciation is $r\%$ per annum. The price of the machine after $n$ years will be _____$\times {\left(1-\frac{r}{100}\right)}^n$.