Question

If a sum of Rs.1000 deposited at compound interest double afteer 4 years .After 20
years, it will become
(a) Rs.20,000
(b) Rs 24,000
(c) Rs.28,000
(d) Rs.32,000

Answer 1

it will be some of Rs. 24,000

Answer 2

Answer:

Rs.32000

Step-by-step explanation:

Principal = Rs.1000

A sum of Rs.1000 deposited at compound interest double after 4 years.

Amount after 4 years = Rs.2000

Formula : $A=P(1+r)^t$

$2000=1000(1+r)^4$

$2=(1+r)^4$

$2^{\frac{1}{4}}=(1+r)$

$1.189207115=(1+r)$

$1.189207115-1=r$

$0.189207115=r$

Now We are supposed to find the amount after 20 years.

$A=1000(1+0.189207115)^{20}$

$A=31999.9999985$

$[tex]A\sim 32000$[/tex]

Hence .After 20  years, it will become Rs.32000