Question

A sum of money becomes 4 times in 20 years at sI. Find the rate of interest

Answer 1

Here is your answer buddy,

Let, The principle = ₹ X

Therefore,

Amount = ₹4X
Time = 20 yrs.

Now, Interest = ₹ Amount - Principle
= ₹ 4X - X
= ₹ 3X
Now, We know that,

Interest = $\frac{PRT}{100}$

=> 3X = $\frac{X×R×20}{100}$

=> 3X = $\frac{X×R×2}{10}$

=> 30X = 2×R×X ( by cross multiplication)

=> $\frac{30X}{X}$ = 2×R

=> R = $\frac{30}{2}$

=> R = 15

Hope this helps you.
Be Brainly.

Answer 2

Concept:

Simple interest is calculated based on a loan's principle or the initial deposit into a savings account. Simple interest doesn't compound, thus a borrower will never have to pay interest on the interest already accumulated because a creditor would only pay interest on the principle amount. Saving, borrowing, and investing all include simple interest, but borrowing usually yields the best results since it prevents debt from accruing over time.

Given:

Here it is given that a sum of money becomes $4$ times in $20$ years at sI.

Find:

We have to find the rate of interest.

Solution:

According to the question, a sum of money becomes $4$ times in $20$ years at sI.

Let, The principle $= X$

Therefore,

Amount$= 4X$

Time $= 20$ yrs.

Now, Interest $=$ Amount $-$ Principle

$= 4X - X\\= 3X$

Now, We know that, Interest$=\frac{PRT}{100}$

So, $\frac{30X}{X} =2R\\or, R=15$

Hence, the rate of interest is $15$.

#SPJ2