At what rate of simple interest per annum an amount will be triple in 10 years?

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At what rate of simple interest per annum an amount will be triple in 10 years?
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Hint: Simple interest is interest calculated on the principal portion of a loan or the original contribution to a saving account. The formula for the simple interest is $S.I. = \dfrac{{P \times R \times T}}{{100}}$. We are going to use the term Amount $A$ in the solution and it stands for sum of simple interest and the principal. It is the amount to which the borrower has to pay after a particular time.

Complete step by step solution:Simple Interest = $S.I.$ (in Rupees)
Amount = $A$ (in Rupees)
Principal =$P$ (in Rupees)
Time = $T$ (in years)
Rate = $R$ (in percentage per annum)
Main goal of the question is to find the time in which the principal will triple to itself. For that we should focus and simplify the given condition.
As given in the question,
In $10$ years principal $P$ becomes $2P$.
In $10$ years,
$A = 2 \times P$
Since Amount $A$ is considered as the sum of principal and the simple interest after $n$ years.
Therefore,
$ \Rightarrow P + S.I. = 2 \times P$
$ \Rightarrow 2P - P = S.I.$
$ \Rightarrow P = S.I.$
As we know the formula for simple interest is $S.I. = \dfrac{{P \times R \times T}}{{100}}$ . On substituting the formula,
$ \Rightarrow P = \dfrac{{P \times R \times T}}{{100}}$
Since it is given that $T = 10$ years.
$ \Rightarrow P = \dfrac{{P \times R \times 10}}{{100}}$
\[ \Rightarrow P = \dfrac{{P \times R}}{{10}}\]
$ \Rightarrow 10 \times P = P \times R$
$ \Rightarrow \dfrac{{10 \times P}}{P} = R$
$ \Rightarrow 10 = R$
Now, by simplifying the given condition we have the rate of interest as $R = 10\% $ per annum.
The time required to triple the principal (say $t$ ) can be found by the formula of Amount and simple interest.
$A = P + S.I.$
$ \Rightarrow 3 \times P = P + S.I.$ [According to question]
$ \Rightarrow 3 \times P - P = S.I.$
$ \Rightarrow 2P = S.I.$
$ \Rightarrow 2 \times P = \dfrac{{P \times R \times t}}{{100}}$
$ \Rightarrow 2 \times P \times 100 = P \times R \times t$
$ \Rightarrow \dfrac{{200 \times P}}{P} = R \times t$
$ \Rightarrow 200 = 10 \times t$
$ \Rightarrow t = 20$

Hence, the time required to triple the principal is $t = 20$ years.

Note: Generally the interest is of two types either simple or compounded. Simple interest is based on the principal amount of a loan or deposit. In contrast, compound interest is based on the principal amount and the interest that accumulates on it in every period.

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Question 1124867: At what simple interest rate will a sum triple itself in 15 years?
Found 2 solutions by amarjeeth223, MathTherapy:
Answer by amarjeeth223(552)
At what rate of simple interest per annum an amount will be triple in 10 years?
 
At what rate of simple interest per annum an amount will be triple in 10 years?
 
At what rate of simple interest per annum an amount will be triple in 10 years?
(Show Source):

You can put this solution on YOUR website!
Let the principal be x.
Then the amount is 3x.
Let the rate be r.
Time=t=15 years
In simple interest amount=P*t*r/100
Plugging in the values we get,
3x=x*15*r/100
Multiplying both sides of the equation by 100 we get,
3x*100=15rx
300x=15rx
15r=300
r=20
The rate of interest is 20%.


Answer by MathTherapy(10229)
At what rate of simple interest per annum an amount will be triple in 10 years?
 
At what rate of simple interest per annum an amount will be triple in 10 years?
  (Show Source):

You can put this solution on YOUR website!

At what simple interest rate will a sum triple itself in 15 years?

It's NOT 20%, as someone claims.
Correct answer:


Let the sum of money be x

Amount = 3 × Rs x

= Rs 3x

Interest = Amount – Principal

= Rs 3x – Rs x

= Rs 2x

Rate =13 \frac{1}{3} \% \text { p.a. }

= 40 / 3 % p.a.

Time (T) = (I × 100) / (P × R)

= (2x × 100) / x × (40 / 3) years

On further calculation, we get,

= (2 × 100 × 3) / 40 years

= (100 × 3) / 20 years

We get,

= 5 × 3 years

= 15 years

At what rate of interest does a simple interest rate triple in 10 years?

⇒R=20%

At what rate of interest compounded annually will an investment triple in 10 years?

Therefore, the interest rate that will triple the investment is 11.61%.

In what time simple interest will a sum of money triples itself at 10%?

⇒T=x×152x×100=340=13. 3 years.

In what duration a sum will be tripled at 10% per annum on simple interest?

Now the amount is tripled. So 10+10=20 years.