Applied Maths Chapter 14 (Ex – 14.1) ML Aggarwal

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Here we provide you with Applied Maths Chapter 14, to help you gain a comprehensive understanding of the chapter and its concepts.

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Applied Maths Chapter 14 Solutions

Compound Interest And Annuity

EXERCISE – 14.1

Q.1 Find the amount and the compound interest on Rs.8000 at 5% per annum for 2 years.

Ans. Principal = Rs.8000 , r = 5% , T = 2 years

Interest on 1st year= (P x R x T)/100

                    = (8000 x 5 x 1)/100

                         = Rs.400

Principal for 2nd year = 8000 + 400

                                    = Rs.8400

Interest on 2nd year=(PxRxT)/100

                       = (8400 x 5 x 1)/100

                       = Rs. 420

Total Interest = 400 + 420    = Rs.820

Total Amount = 8000 + 820 = Rs.8820

Q.2 A man invests Rs.46875 at 4% per annum compound interest for 3 years. Calculate:

(i) the interest for the first year.

(ii) the amount standing to his credit at the end of the second year.

(iii) the interest for the third year.

Ans.

(i) Interest for 1st year = (PxRxT)/100

= (46875 x 4 x 1)/100

= Rs.1875

(ii) Principal for 2nd year =

46875 + 1875

   = Rs.48750

 Interest for 2nd year =

(PxRxT)/100

  = (48750 x 4 x 1)/100

  = Rs. 1950

Amount at the end of 2nd year = 46875 + 1875 + 1950

      = Rs.50700

(iii) Principal for 3rd year = Rs.50700

Interest for 3rd year = (PxRxT)/100

                  = (50700 x 4 x 1)/100

                  = Rs. 2028

Q.3  A man invests Rs.5000 for three years at a certain rate of interest, compounded annually.        At the end of one year, it amounts to Rs.5600. Calculate:

 (i) the rate of interest per annum.

(ii) the interest accrued in the second year.

(iii) the amount at the end of the third year.

Ans.

(i) Principal = Rs.5000 , r = ? , A = Rs.5600

Interest for 1st year = 5600 – 5000

                                  = Rs. 600

      Therefore,

      Interest = (P x R x T)/100

           600   = (5000 x R x 1)/100

             R  = 12%

(ii) Principal for 2nd year = Rs.5600

Interest on 2nd year = (PxRxT)/100

                     = (5600 x 12 x 1)/100

                     = Rs. 672

(iii) Principal for 3rd year =

5600 + 672

   = Rs.6272

Interest for 3rd year = (PxRxT)/100

                   = (6272 x 12 x 1)/100

                   = Rs. 752.64

           Amount = 6272 + 752.64

                           = Rs.7024.64

Q.4 Find the amount and the compound interest on Rs.2560 for 1 1/2 years at 6 1/4% per annum the, interest being compounded semi-annually.

Ans. Principal = Rs.2560, T = 1 1/2 = 3 half year (semi-annually),

r = 6 1/4% = 25/4%

   Interest for semi-annually = (25/4) x (1/2) = 25/8% 

Interest on 1st half year = (PxRxT)/100

   = (2560 x 25 x 1)/(100 x 8)

    = Rs.80

Principal for 2nd half year =

2560 + 80

  = Rs.2640

Interest for 2nd half year = (PxRxT)/100

= (2640 x 25 x 1)/(100 x 8)

= Rs. 82.5

Principal for 3rd half year = 2640 + 82.5

   = Rs.2722.50

Interest for 3rd half year = (PxRxT)/100

 = (2722.50 x 25 x 1)/(100 x 8)

  = Rs. 85.08

Amount at the end of 3rd year = 2722.50 + 85.08      

   = Rs.2807.58

   Interest = 2807.58 – 2560

                 = Rs.247.58

Q.5 A man saves ₹4000 every year and invests it at the end of the year at 10% per annum compound interest. Calculate the total amount of his savings at the end of the third year.

Ans.

Principal = Rs.4000 , r = 10% , T = 3

Interest for 1st year = (PxRxT)/100

                      = (4000 x 10 x 1)/100

                      = Rs.400

Principal for 2nd year = (Amount at the end of 1st year + his new savings)

     = 4000 + 400 + 4000

     = Rs.8400

Interest for 2nd year = (PxRxT)/100

                   = (8400 x 10 x 1)/100

                   = Rs. 840

Principal for 3rd year = (Amount at the end of 1st year + his new savings)

       = 8400 + 840 + 4000

        = Rs.13240

Interest for 3rd year = (PxRxT)/100

                     = (13240 x 10 x 1)/100

                     = Rs.1324

        Therefore,

Total amount of savings at the end of 3rd year

             = Rs.13240

Q.6 Calculate the amount and the compound interest on Rs.17000 in 3 years when the rate of interest for successive years is 10%, 10%, and 14% respectively.

Ans.

Interest for 1st year = (PxRxT)/100

                    = (17000 x 10 x 1)/100

                     = Rs.1700

Principal for 2nd year = 17000 + 1700

                                   = Rs.18700

Interest for 2nd year = (PxRxT)/100

                    = (18700 x 10 x 1)/100

                    = Rs. 1870

Principal for 3rd year = 18700 + 1870

                                   = Rs.20570

Interest for 3rd year = (PxRxT)/100

                     = (20570 x 14 x 1)/100

                     = Rs. 2879.8

           Amount = 20570 + 2879.8

                           = Rs.23449.8

            Interest = 23449.8 – 17000

                           = Rs.6449.8

Q.7 The simple interest on a certain sum of money for 2 years at 10% per annum is Rs.1600. Find the amount due and the compound interest on this sum of money at the same rate after 3 years, interest being reckoned annually.

Ans.

Simple Interest = (P x R x T)/100

          1600  = (P x 10 x 2)/100

       (1600 x 100)/(10 x 2) = 8000 P

             P = Rs.8000

 Interest for 1st year = 1600/2 = Rs.800

Principal for 2nd year = 8000 + 800

                                     = Rs.8800

Interest for 2nd year = (PxRxT)/100

                   = (8800 x 10 x 1)/100

                   = Rs. 880

Principal for 3rd year = 8800 + 880

                                    = Rs.9680

Interest for 3rd year = (PxRxT)/100

                    = (9680 x 10 x 1)/100

                   = Rs. 968

Amount at the end of 3rd year = 9680 + 968

       = Rs.10648

Interest = 10648 – 8000

                = Rs.2648

Q.8  A man invests Rs.4000 for three years at compound interest. After one year the money amounts to Rs.4320. Find the amount (to the nearest rupee) due at the end of 3 years.

Ans.

Interest for 1st year = 4320 – 4000

                                 = Rs.320

      Therefore,

Interest = (P x R x T)/100

     320  = (5000 x R x 1)/100

           R  = 8%

   Principal for 2nd year = Rs.4320

Interest on 2nd year = (PxRxT)/100

                       = (4320 x 8 x 1)/100

                       = Rs.345.6

Principal for 3rd year =

4320 + 345.6

    = Rs.4665.6

Interest for 3rd year = (PxRxT)/100

               = (4665.6 x 8 x 1)/100

               = Rs.373.248

           Amount = 4665.6 + 373.248

            = Rs.5038.848 = Rs.5039 (round off)

Q.9 A man borrows Rs.15000 at 14% per annum compound interest. If he repays Rs.4300 at the end of the first year and Rs.5220 at the end of the second year, find the amount of loan outstanding at the beginning of the third year.

Ans.

Interest for 1st year = (PxRxT)/100

                  = (15000 x 14 x 1)/100

                  = Rs.2100

Principal for 2nd year = 15000 + 2100 – 4300 

                              = 17100 – 4300

                              = Rs.12800

Interest for 2nd year = (PxRxT)/100

               = (12800 x 14 x 1)/100

                = Rs. 1792

Principal for 3rd year = 12800 + 1792 – 5220

     = 14592 – 5220 = Rs.9372

           Therefore,

Amount of laon outstanding at the beginning of the third year = Rs.9372

Q.10 Vikram borrowed 20000 from a bank at 10% per annum simple interest. He lent it to his friend Venkat at the same rate but compounded annually. Find his gain after 2 1/2 years.

Ans.

Interest paid by Vikram for = 2 1/2 = 5/2 years

           S.I = (P x R x T)/100

         = (20000 x 10 x 5)/(2 x 100)

                = Rs.5000

       For Venkat

Interest for 1st year = (PxRxT)/100

          = (20000 x 10 x 1)/100

          = Rs.2000

Principal for 2nd year =

20000 + 2000 

 = Rs.22000

Interest for 2nd year = (PxRxT)/100

                    = (22000 x 10 x 1)/100

                    = Rs.2200

Principal for next half year =

22000 + 2200

  = Rs.24200

Interest for next half year =(PxRxT)/100

= (24200 x 10 x 1)/(100 x 2)

= Rs.1210

Total interest paid by Venkat = 2000 + 2200 + 1210

       = Rs.5410

          Therefore, 

   gain by Vikram = 5410 – 5000

                              = Rs.410

Q.11 Sachin invests Rs.200000 for 2 years at 12% per annum compounded annually. If the interest accrued is subject to income tax at 25% at the end of each year, find the amount he received at the end of 2 years.

Ans.

Interest for 1st year = (PxRxT)/100

               = (200000 x 1 x 12)/100

                = Rs.24000

  Tax = 24000 x 25/100 = Rs.6000

   Gain after 1 year = 24000 – 6000

                                = Rs.18000

Principal for 2nd year =

200000 + 18000 

            = Rs.218000

Interest for 2nd year = (PxRxT)/100

            = (218000 x 12 x 1)/100

            = Rs.26160

  Tax = 26160 x 25/100  = Rs.6540

  Gain after 2 years = 26160 – 6540

                                 = Rs.19620

       Amount at the end of 2 year = 218000 – 19620

            = Rs.237620

FAQ’s related to Applied Maths Chapter 14 on compound interest and annuity:

Q.1 What is compound interest, and how does it differ from simple interest?

Ans. Compound interest is the interest calculated on the initial principal and also on the accumulated interest from previous periods. Unlike simple interest, which is calculated only on the principal amount, compound interest takes into account the interest earned over time, resulting in exponential growth of the investment.

Q.2 What are some common mistakes to avoid when solving compound interest and annuity problems?

Ans. Common mistakes include misinterpreting the problem statement, using incorrect formulas, neglecting to convert interest rates to decimal form, and misunderstanding the frequency of compounding or payment periods. It’s essential to carefully read the problem and double-check calculations for accuracy.

Q.3 How do I calculate compound interest for a given principal, interest rate, and time period?

Ans. The formula to calculate compound interest is A = P(1 + r/n)^(nt), where A is the future value, P is the principal amount, r is the annual interest rate (in decimal form), n is the number of times interest is compounded per year, and t is the time in years.

These are few Frequently Asked Questions relating to Applied Maths Chapter 14

In Applied Maths chapter 14, you will explore fascinating topics that form the backbone of practical problem-solving techniques. Through clear explanations, illustrative examples, and step-by-step solutions, you’ll grasp complex concepts effortlessly. Whether you’re preparing for exams or simply eager to deepen your mathematical understanding, Applied Maths Chapter 14 promises an enriching learning experience that will set you on the path to success. Applied Maths Chapter 14, we delve deep into advanced mathematical concepts that are crucial for understanding.

Applied Maths Chapter 14 EXCERCISES:

Exercise- 14.1https://appliedmathsolution.com/wp-admin/post.php?post=12&action=edit
Exercise- 14.2https://appliedmathsolution.com/wp-admin/post.php?post=19&action=edit
Exercise- 14.3https://appliedmathsolution.com/wp-admin/post.php?post=43&action=edit
Exercise-14.4https://appliedmathsolution.com/wp-admin/post.php?post=48&action=edit

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3 Comments

  1. Hi I am Rahul Rajaji ,
    This is regarding the mistake to be changed
    I am Studying in class 11th
    Please change the mistake in exercise 14.1 question number 2 subdivision 2 . amount of second year is 1950 + 48750 = 50700 but in your website there is an addition mistake like 1950 + 48750 + 1875 = 50700 . Its my request you Kindly change this which can confuss the students .

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