Question

Sum of rs.12000 deposited at compound interest become double after 5 years.After 20 years it will become

Answer 1

12000 double in 5 years

after 5 years = 24000
after 5 years = 48000
after 5 years =96000
after 5 years = 1,92,000
after 20 years it will be 192000

Answer 2

Answer:

After 20 years it will become Rs 192000

Explanation:

Given data

principal = Rs 12000

time = 5 year

to find out

amount after 20 year

solution

we know that after 5 year amount will be double that is Rs 24000

so we will apply here formula that is

amount = principal$(1+r/100)^{t}$   ...............1

here r is rate and t is time period

so in 1st case we have 5 year time and amount 24000 and principal 12000

so

24000 = 12000 $(1+r/100)^{5}$

2 = $(1+r/100)^{5}$

so we find after 20 year i.e 5×4 =20

$2^{4}$ = $(1+r/100)^{5*4}$

16 =  $(1+r/100)^{20}$

so we multiply here with principal  12000

principal (16) = principal (  $(1+r/100)^{20}$  )

12000 (16) = 12000 (  $(1+r/100)^{20}$  )

we can see here principal (  $(1+r/100)^{20}$  ) this is amount formula for 20 year

so

amount = 12000 (16) = 192000

so After 20 years it will become Rs 192000