Question

21. A sum of money becomes 8/5 of itself in 5 years at a certain rate of simple interest. Find the
rate of interest.​

Answer 1

Answer:32%

Step-by-step explanation:

Simple interest =Prt/100

Let the principal be x.

8x/5 = x*r*5/100

8*100x/5*5*x=r

Cut x

R=800/25

R=32

Answer 2

Answer:

Step-by-step explanation:

Let initial sum = 100

Now in 5 years ( initial sum + interest ) becomes 8/5 th of the Initial sum = 160*8/5 =160

so the interest in 5 years is now ( initial sum + interest) - initial sum = 160-100 =60

so Rs 100 gets in 5 years 60 rs of interest

so. Rs 100 gets in 1 year 60/5 = 12 Rs of interest

so the Rate of interest is 12% (Answer)