Question

A sum of money becomes 8/5 of itself in 5 year's at a certain rate of simple intrest .find the rate of interest​

Answer 1

HII USER

IT'S SIMPLE

Rate of simple interest = 12%

Step-by-step explanation:

Let the Initial principle amount = P

After 5 years the amount received  = (8/5)P

As the interest applicable is simple interest, the total interst accumilatedis Final amount received - Initial principle amount.

Interest amount for 5 years = (8/5)P - P

Interest amount for 5 years = (3/5)P

With simple interest, interest amunt every year is the same.

Thus interest for one year = Interst for 5 years / 5

Interest for one year = (3/5)P / 5

Interest for one year = (3/25)P

Simple Rate of interest per year = (Amount of Interest received per year / Initial Principle amount) × 100%

∴ Rate of interest per year = ((3/25)P ÷ P) × 100 %

∴ simple rate of interest = (3÷25) ×100 %

∴ Simple Rate of interest = 12 %