Question

2) Mr. Johnson saves Rs.80 every month and puts in a
recurring deposit scheme paying 8% simple interest per
annum.In order to receive a total amount of Rs.5776, how
many monthly installments must be deposited ?​

Answer 1

Given: Mr. Johnson saves Rs.80 every month and puts in a  recurring deposit scheme paying 8% simple interest per  annum.

To find: How  many monthly installments must be deposited ?​

Solution:

• Now let x be the monthe that he saved Rs 80.

• Interest for 1 month will be:

                  Rs 80 x 8/100 x x/12

• Interest for 2nd month will be:

                  Rs 80 x 8/100 x (x - 1)/12

• Similarly, the interest of last month will be:

                  Rs 80 x 8/100 x 1/12

• So the total amount will be:

                  Rs 80x + (Rs 80 x 8/100 x x/12)  + (Rs 80 x 8/100 x (x - 1)/12) + .....+(Rs 80 x 8/100 x 1/12) = 5776

                  80x + (80 x 8/100) x 1/12{ x + x-1 + x-2 + ........+ 1} = 5776

                  10x + x(x+1)/15x2 = 722

                  300x + x^2 + x = 21660

                   x^2 + 301x - 21660 = 0

• So x comes out to be 60.

Answer:

               So for 60 months installments must be deposited.

Answer 2

Answer:

5years

Step-by-step explanation:

kindly check attached file.