A sum of money will double itself in 4 years at simple interest with a yearly rate of ___________ %.Choices:- 20 25 30 35

The formula for simple interest is I = PRT, where I is the interest, P is the principal amount (the initial amount of money), R is the rate of interest, and T is the time in years.

In this case, the sum of money doubles itself in 4 years. This means that the interest (I) is equal to the principal amount (P). So, we can rewrite the formula as P = PRT.

We can simplify this to 1 = RT, since P/P = 1.

We know that T = 4 years, so we can substitute this into the equation to get 1 = R*4.

Solving for R, we get R = 1/4 = 0.25.

To convert this to a percentage, we multiply by 100, so R = 25%.

Therefore, the yearly rate of interest is 25%.

The formula for simple interest is I = PRT, where I is the interest, P is the principal amount (the initial amount of money), R is the rate of interest, and T is the time in years.

In this case, the sum of money doubles itself in 4 years, so the interest (I) is equal to the principal (P).

So, we can set up the equation as follows:

P = P * R * 4

Solving for R (the rate of interest), we get:

R = 1 / 4 = 0.25

Therefore, the yearly rate of interest is 25%. So, the correct choice is 25.