At what rate of simple interest will a sum of money treble itself in 40 years?

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Solution

The correct option is A 20 yearsLet the principal be P. As per the question, Amount = 2(Principal) = 2P SI = Amount - Principal = 2P - P = P By formula, R=SI×100P×T R=P×100P×10 =10 % So, the rate is 10% per annum. Now, the sum gets tripled. A = 3(Principal) = 3P SI = 3P - P = 2P T=SI×100P×R T=2P×100P×10 = 20 years

At what rate will a sum of money double itself in 16 years?

= P and T = 16 yrs. Rate = 100 x P/P*16% = 6 ¼ % p.a.

How long will it take a sum of money to treble itself at 16% pa simple interest?

A sum of money triple itself at 16% p.a. at simple interest in 12.5 years.

In what time will a sum of money put at 15 simple interest triple itself?

So the answer for your question is 13Y and 4 months.

At what rate percent per annum simple interest will a sum travel itself in 16 years?

⇒R=2P×100P×16=12.5%

Answer

Verified

Hint: We will assume the sum invested as x rupees. We have been given that it becomes triple after 3 years which means it becomes 3 x. Now, we know that the final amount = principal amount + simple interest. So, we will find the simple interest from that and using the formula, $\text{simple interest}=\dfrac{\text{principal amount}\times \text{time}\times \text{rate}}{100}$, we will find the rate of interest.

Complete step-by-step answer:
We are given the time period as 16 years and that the sum becomes triple after 16 years. So, we will first assume the sum invested as Rs. x. We have been given that after 16 years, it becomes triple, so,
Final amount = $3\times x=3x$.
Now, we know that the final amount is the summation of the principal amount and simple interest,
Final amount = principal amount + simple interest, which can be written as,
3 x = x + simple interest, so we get the simple interest as = 3 x - x = 2 x.
Now, we have the principal amount, time and the simple interest, so we will find the rate using the formula, $\text{simple interest}=\dfrac{\text{principal amount}\times \text{time}\times \text{rate}}{100}$. So, by substituting the values of the parameters we get,
$\begin{align}
  & \dfrac{2x}{1}=\dfrac{x\times 16\times rate}{100} \\
 & \Rightarrow \dfrac{2}{1}=\dfrac{16\times rate}{100} \\
\end{align}$
On cross-multiplying, we get,
$\begin{align}
  & rate=\dfrac{2\times 100}{16} \\
 & \Rightarrow rate=12.5\% \\
\end{align}$
Hence, we get the rate of interest as 12.5 %.

Note: There is a possibility that the students think that the simple interest becomes triple of the principal amount, that is simple interest is 3 x. So, in further calculations for finding the rate of interest, they will end up with, $rate=\dfrac{3\times 100}{16}\Rightarrow 18.75\%$. But students should read the question carefully to understand that the sum becomes triple, which means the principal amount becomes triple after 16 years.

At what rate of SI per annum a sum triples itself in 40 years?

At what rate of simple interest will a sum trebles itself in 20 years?

At what rate of interest a sum of money will be trebles itself in 5 years?

At what rate of simple interest will a sum of money treble itself in 25 years?