Question

At the rate of any compound interest rate, it gets tripled in 4 years, in how many years it will
become 2187 times its own?

Answer 1

Answer:

Time = 28 years

Step-by-step explanation:

$A = P(1+\frac{r}{100} )^n$

It gets tripled in 4 years.

$3 = 1 (1+\frac{r}{100} )^4$

$(1+\frac{r}{100} ) = 3^{\frac{1}{4} }$

Now, time in which it would amount becomes 2187 times

$2187 = 1 (1+\frac{r}{100} )^n$

Keeping the value of $(1+\frac{r}{100} ) = 3^{\frac{1}{4} }$

$2187 = (3^{\frac{1}{4} })^n$

$3^7 = 3^{\frac{n}{4} }$

Comparing the same bases :

7 = n/4

n = 7 *4 = 28