Question

A sum of rs 2000 amounts to rs 4000 in two years at compound interest in how many years does the same amount becomes rs 8000

Answer 1

it will takes four years.

Answer 2

Answer:

4 years

Step-by-step explanation:

Given :A sum of rs 2000 amounts to rs 4000 in two years at compound interest.

To Find:In how many years does the same amount becomes rs 8000

Solution:

A sum of rs 2000 amounts to rs 4000 in two years.

Formula : $A=p(1+\frac{r}{100})^t$

A = Amount = 4000

P = Principal = 2000

t = time = 2 years

r = rate of interest in percent

Substitute the value in the formula

$4000=2000(1+\frac{r}{100})^2$

$2=(1+\frac{r}{100})^2$

$\sqrt{2}=(1+\frac{r}{100})$

$1.41=(1+\frac{r}{100})$

$41.4 = r$

Now amount is 8000

So, To calculate how many years does the same amount becomes rs 8000

So,  $8000=2000(1+\frac{41.4}{100})^t$

$t=4.00017$

Thus Rs. 200 becomes Rs.8000 in 4 years.