a sum of money doubles in 20 years on simple interest, it will triple at the same rate in how many years?

To find out how many years it will take for the sum of money to triple at the same rate of simple interest, we can use the formula for simple interest:

I = P * r * t

Where: I = Interest earned P = Principal amount (initial sum of money) r = Interest rate per year t = Time in years

In this case, we know that the sum of money doubles in 20 years on simple interest. This means that the interest earned after 20 years is equal to the principal amount (P). Therefore, we can rewrite the formula as:

P = P * r * 20

Simplifying the equation, we get:

1 = r * 20

Now, we need to find out how many years it will take for the sum of money to triple. Let's call this unknown time "t2". Using the same formula, we have:

3P = P * r * t2

Simplifying the equation, we get:

3 = r * t2

Now, we can set up a proportion to solve for t2:

1/20 = 3/t2

Cross-multiplying, we get:

t2 = 20 * 3

t2 = 60

Therefore, the sum of money will triple at the same rate of simple interest in 60 years.