Question

A sum of money amounts to Rs. 40080 in 3 years and to Rs.75087 in 10 years, at simple interest. Find the sum and rate percentage of interest.

Answer 1

Answer:

Step-by-step explanation:

A sum of money amounts to Rs. 2502 in three year and Rs. 3087 in five and a half year at the same rate of simple interest per annum.

Formula used:

simple interest = (principal × rate × time)/100

Calculation:  

Let the principal be 'P' and rate of interest = r%

In three year, amount = Rs. 2502

In five and a half year, amount = Rs. 3087

⇒ (5.5 - 3) year = Rs. (3087 - 2502)

so, 2.5 year = Rs. 585

⇒ 1 year = 585/(2.5) = Rs. 234

In three year = (585 × 3)/2.5 =Rs. 702

⇒ principal (P) = Rs. (2502 - 702) = Rs.1800

⇒ rate of interest (r) = (234/1800) × 100

⇒ r = 13%

∴ The required Rate of interest is 13%.