S.chand Class 8 Maths Solution Chapter 9 Compound Interest Exercise 9 B

 Exercise 9 B

Calculate the amount and the compound interest by using the formula for compound interest.

Question 1

Principal	Rate of Interest	Time (in years)
1. ₹625	4% p.a	2
2.₹1000	10% p.a.	3
3.₹8000	10% half-yearly	$1 \frac{1}{2}$

4. Reena and Ruchira borrowed $₹ 60,000$ and $₹ 50,000$ respectively for a period of 3 years. Reena paid simple interest at the rate of $10 \%$ p.a., while Ruchira paid compound interest at the rate of $10 \%$ p. a. compounded annually. Who paid more interest and by how much ?

5. Sangeeta lent $₹ 40,960$ to Amar to purchase a shop at $12.5 \%$ per annum. If the interest is compounded semi-annually, find the interest paid by Amar after $1 \frac{1}{2}$ years.

6. Sudhir lent $₹ 2,000$ at compound interest at $10 \%$ payable yearly, while Prashant lent $₹ 2,000$ at compound interest at $10 \%$ payable half-yearly. Find the difference in the interest received by Sudhir and Prashant at the end of one year.

7. Find the difference between the simple interest and compound interest on $₹ 16,000$ for $1 \frac{1}{2}$ years at $5 \%$ per annum, compound interest being reckoned half yearly.

8. Find the compound interest on $₹ 3,125$ for 3 years if the rates of interest for the first, second and third year are respectively $4 \%, 5 \%, 6 \%$.

9. A district contains 64,000 inhabitants. If the population increases at the rate of $2 \frac{1}{2} \%$ per annum, find the number of inhabitants at the end of 3 years.

10. The Nagar Palika of a certain city started campaign to kill stray dogs which numbered 1,250 in the city: As a result, the population of stray dogs started decreasing at the rate of $20 \%$ per month. Calculate the number of stray dogs in the city three months after the campaign started.

11. The value of a machine depreciates each year by $10 \%$ of its value at the beginning of that year. Its value when new is $₹ 750$; find its value when it is 2 years old.

12. The national wealth of a country increases by $4 \%$ of its value at the beginning of every year. Find the national wealth of the country in 1985 , if it was estimated at $₹ 3.125 \times 10^{12}$ in 1983 .

13. The price of a scooter depreciates by $2 \%$ of its value at the beginning of each year. Find the sale value of the scooter after 3 years, if its present sale value is $₹ 12,000$.

14. The population of Andhra Pradesh was $5.4 \times 10^{7}$ in 1988. If the population was growing at a constant rate of $2.4 \%$ per annum, what was the population in 2008 A.D. [Given that $(1.024)^{20}=1.60694$ ]

Multiple Choice Questions (MCQs)

15. A steno-typist deposits $₹ 10,000$ in a bank for a period of 3 years at $12 \%$ per annum compound interest. The interest accrued to her after maturity will be

(a) $₹ 3600$

(b) ₹ 4029

(c) ₹ 4032

(d) ₹ $4049.28$

16. The present population of a city is $1,80,000$. If it increases at the rate of $8 \%$ per annum, its population after 2 years will be

(a) $2,07,800$

(b) $2,09,952$

(c) 2,05,992

(d) $2,08,700$

High Order Thinking Skills (HOTS)

17. Umesh set up a small factory by investing $₹ 40,000$. During the first three successive years his profits were $5 \%, 10 \%$ and $15 \%$ respectively. If each year the profit was on previous years' capital, calculate his total profit.

(a) ₹ 35,900

(b) ₹ 13,130

(c) ₹ 11,330

(d) ₹ 33,110

18. The price value of the share of a company increased at the rate of $15 \%$ in the first year, suffered a loss of $10 \%$ in the next year and again increased by $20 \%$ in the third year. If the present value of the share is $₹ 2000$, what will be its value after 3 years