Question

Certain sum amount to Rs.9440 in 3 years and Rs.10400 in 5 years.Find the sum and rate percentage.

Answer 1

10400-9440=960 this int for 2 years
960/2=480 per year
9440-(460*3)=8000
amount
8000*6%=480 so int is 6% p.a

Answer 2

The sum is Rs. 7990 and the interest is 5.88%.

Step-by-step explanation:

Let us assume the r% simple interest is applicable to a principal of P Rs.

Now, after 3 years the sum becomes Rs. 9440 and after 5 years, the sum becomes Rs. 10400.

Therefore, $9400 = P(1 + \frac{3r}{100})$ ......... (1) and

$10400 = P(1 + \frac{5r}{100} )$ ......... (2)

Now, dividing (2) with (1) we get

$\frac{(1 + \frac{5r}{100} )}{(1 + \frac{3r}{100})} = \frac{10400}{9440}$

⇒ 1 + 0.05r = 1.1(1 + 0.03r)

⇒ 1 + 0.05r = 1.1 + 0.033r

⇒ 0.017r = 0.1

⇒ r = 5.88%

Now, from equation (1) we get.

$9400 = P(1 + \frac{3\times 5.88}{100})$

⇒ P = 7990 Rs.

Therefore, the sum is Rs. 7990 and the interest is 5.88%. (Answer)