Question

A sum of money triples itself in 18 years under simple interest. What is the rate of interest per annum?​

Answer 1

Answer:

rate of interest = 11.1%

Answer 2

The  interest rate  is 11.11 per annum.

Step-by-step explanation:

Given:

The  sum of money triples itself in 18 years in simple interest.

To- Find:

The   interest rate per annum.

Formula Used:

$SI=\frac{ MRS}{100}$              --------------------- Formula no 1.

Where

SI = Simple Interest

M = Principal value

R = Interest rate (in percentage)

S= Time duration (in years)

Amount  = Principal  +  Simple Interest   --------- Formula no.2.

Solution:

As given-a sum of money triples itself in 18 years in simple interest.

Principal = M ,   Amount = 3M   and S=18 years

Applying  Formula no.2.

Amount  = Principal  +  Simple Interest

$3M = M + Simple\ Interest$

$Simple\ Interest=3M-M$

$Simple\ Interest(SI)=2M$

Applying  Formula no.1.  

$SI=\frac{ MRS}{100}$

$2M=\frac{ M\times R\times 18}{100}$

$2M\times100=M\times R\times 18$

$R=\frac{200M}{18M}$

   $=11.11 per\ annum.$

Thus, the  interest  rate  is 11.11 per annum.

PROJECT CODE  # SPJ3