If any principal becomes double in 10 years then what is the rate of profit?

Question

rate of profit mathematics problem.

Answer 1

If interest is simple then,

SI = prt/100

where, SI= simple interest, p=principal, r=rate and t=time

Given, SI = p and t=10

so, p = 10pr/100

=> 1 = r/10

or r=10

So rate must be 10%

If it is compound interest then

A = p(1+r/(n*100))^t

where A = new amount = 2p and n = compounding frequency

so, 2p = p(1+r/(n*100))^10n

2 = (1+r/(n*100))^10n

2^(1/10n) = 1 + r/(n*100)

(n*100)(2^(1/10n) - 1) = r

or r = (n*100)(2^(0.1n) - 1)