S Chand ICSE Mathematics Class 9 Solution Second Chapter Compound Interest Exercise 2B
Calculate the amount and the compound interest by using the formula for compound interest.
Principal | Rate of Interest | Time (in years) | |
(1) |
Rs. 625 | 4% | 2 |
(2) |
Rs. 8000 | 15% |
3 |
(3) |
Rs. 1000 | 10% |
3 |
(4) |
Rs. 8000 |
10% half yearly |
1 and 1/2 |
(5) |
Rs. 700 | 20% half yearly |
1 and 1/2 |
Solution:
(6) Sangeeta lent Rs. 40960 to Amar to purchase a shop at 12.5% per annum. If the interest is compounded semi-annually, find the interest paid Amar after 1 and ½ years.
Solution:
(7) Sudhir lent Rs. 2000 at compound interest at 10% payable yearly, while Prashant lent Rs. 2000 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.
Solution:
Difference between interest = (205 – 200) Rs.
= 5 Rs.
(8) How much will Rs. 25000 amount to in 2 years at compound interest, if the rates for the successive years be 4 and 5 per cent per year?
(9) Umesh set up a small factory by investing Rs. 40,000. During the first three successive his profits were 5%, 10% and 15% respectively. If each year the profit was on previous year’s capital, calculate his total profit.
(10) Himachal Pradesh State electricity Board issued in July 1988, 20 year bonds worth Rs. 6.25 crore. The issue price of each bond is Rs. 100 and it carries an annual interest of 11.5% compounded half yearly. Jasbir invested Rs. 5000 in these bonds. Find the amount that he gets on maturity of the bonds in 2008.
Solution:
(11) A district contains 64000 inhabitants. If the population increases at the rate of 2 and 1/2% per annum, find the number of inhabitants at the end of 3 years.
(12) The Nagar Palika of a certain city started campaign to kill stray dogs which number 1250 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.
(13) 8000 blood donors were registered with a charitable hospital. Some student organizationas started mobilizing people for this noble cause. As a result, the number of donors registered, increased at the rate of 20% per half years. Find the total number of new registrants during 1 and 1/2 years.
Solution:
∴ Total number of new registrants = (800 + 880 + 968)
= 2648