Question

a sum of amount as r% compound interest doubles in 3 years . In 9 years it will be k times of original principal . find the value k . pls help me with this question . with correct explanation pls . I will mark as brainlist and will give you 30 thanks. spamming will be reported
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Answer 1

Step-by-step explanation:

A sum becomes double in 3 years

If Principal is 'P'

2P

4P

8P

3 years

6 years

9 years

Hence, it becomes '8' times in 9

years.

ALTERNATE:

A = P[1+ r/100]^n =

A= 2P in 3 years

2P = P[1+ r/100]^3 'p' both LHS and RHS]

[dividing by

2 = [1+ r/100]^3.(1)

kP = P[1+ r/100)^9

k= [1 + r/100]^9 .i)

On cubing the eq. (i)

2^3 = { [1 + r/100)^3)^3

8 = [1 + r/100]^9.(i)

k= 8

Hence, 8 times