Question

10. A sum of money becomes eight times in 3 years. If
the rate is compounded annually, in how much time
will the same amount at the same compound rate
become sixteen times?​

Answer 1

Answer:

Let the money = x and rate of interest = r

As per questions, 8x = x(1+r/100)^3

Or, 2^3 = (1+r/100)^3

Or, 2 = 1+r/100

Or, r/100 = 2–1

Or, r = 100

So, rate of interest is 100%

Again, 32x = x(1+100/100)^n [n = no of years]

Or, 32 = (1+1)^n

Or, 2^5 = 2^n

Or, n = 5

Answer 2

Step-by-step explanation:

Let the money = x and rate of interest = r

As per questions, 8x = x(1+r/100)^3

Or, 2^3 = (1+r/100)^3

Or, 2 = 1+r/100

Or, r/100 = 2–1

Or, r = 100

So, rate of interest is 100%

Again, 32x = x(1+100/100)^n [n = no of years]

Or, 32 = (1+1)^n

Or, 2^5 = 2^n

Or, n = 5