Class 8 Compound Interest

Transcription

1 ID : in-8-compound-interest [1] Class 8 Compound Interest For more such worksheets visit Answer the questions (1) Number of employees in a company increases by 30% every year. If there are 6000 employees in the company, find the number of employees in company after 2 years. (2) Find compound interest on s. 0 for 6 months at 12% per annum compounded half yearly. (3) Find compound interest on s for 2 years at % per annum compounded annually. (4) Pradip bought a plot at s If its value appreciates at the rate of % per annum, find the value of the plot after 2 years. (5) ia borrowed s from a bank at the interest rate of % per annum compounded annually. What would be the amount payable to bank after 3 years? (6) At the rate of % per annum compounded annually, how long would it take for a sum of s to compound to s (7) Find compound interest on s for 2 years and 6 months at 20% per annum compounded annually. (8) Population of a town increases by 2% every year. If current population of the town is Find the population of town after 2 years Edugain ( All ights eserved Many more such worksheets can be generated at

2 Answers ID : in-8-compound-interest [2] (1) 140 It is given that number of employees increases at a compounding rate of 30% yearly. Number of employees in the company (P) = 6000 Yearly compounding rate () = 30% Time (n) = 2 years Using compound interest formula, Number of employees after 2 years = P(1 + = 6000( ) 2 = 6000 (1.3) 2 = = 140 Therefore, the number of employees in the company after 2 years is 140.

3 (2) s. 60 ID : in-8-compound-interest [3] We have been asked to find the compound interest on s. 0 for 6 months at 12% per annum compounded half yearly. Principal, P = s. 0 Number of terms, n = Number of half years in 6 months = 1 Interest ate per annum = 12%, Interest ate per term of half year, = 12% 2 = 6% Amount = P(1 + 6 = 0(1 + = = s. 60 ) 1 Compound Interest = Amount - Principal = 60-0 = s. 60 Step 5 Therefore, the compound interest is s. 60.

4 (3) s. 50 ID : in-8-compound-interest [4] We have been asked to find the compound interest on s for 2 years at % per annum compounded annually. Principal, P = s ate, = % Time, n = 2 years Amount = P(1 + = 5000(1 + ) 2 = 5000(1.1) 2 = = s Compound interest = Amount - Principal = = 50 Therefore, the compound interest is s. 50. (4) s We have been asked to find the value of the plot after 2 years. Principal, P = s ate, = % Time, n = 2 years Amount = P(1 + = (1 + = = ) 2 Therefore, the value of plot after the 2 years is s

5 (5) s ID : in-8-compound-interest [5] It is given that, Principal, P = s ate, = % Time, n = 3 years Amount = P(1 + = 7000(1 + = = 9317 ) 3 Therefore, the amount payable to the bank after 3 years is s (6) Three years Let the time be n years. According to the question, Principal, P = s ate, = % Amount = s Let's find the time. Amount = P( = 20000( = ( 1 ( 11 n = 3 ) 3 = ( 11 Therefore, in 3 years, s will become s at % per annum compounded annually.

6 (7) s ID : in-8-compound-interest [6] Principal, P = s ate, = 20% Time, n = 2 yearss and 6 months = years For first 2 years, interest can be calculated using compound interest formula, Amount = P [1 + ] n Amount = [1 + = = s ] 2 Since interest is compounded annually only, interest for remaining 6 month should be calculated as simple interest on a principal of s , Amount after simple Interest for 6 months = [1 + (6/12)20 ] = = s Total interest = Amount - Principal = s Step 5 Therefore, the total compound interest is s

7 (8) ID : in-8-compound-interest [7] Since population increases by 2% annually, we can use compound interest formula where current population can be considered as principal. Current population or principal, P = ate, by which population increases every year = 2% Time, n = 2 years Population of the town after 2 years or Amount = P [1 + ] n 2 = [1 + = = ] 2 Therefore, the population of the town after 2 years will be