Select the correct answerA sum of money in 3 years becomes 1344 and in 7 years it becomes Rs. 1536. What is the principal sum where simple rate of interest is to be unchanged?Options63000240003600012000

The problem is about simple interest. The formula for simple interest is I = PRT, where I is the interest, P is the principal, R is the rate, and T is the time.

Given that a sum of money becomes 1344 in 3 years and 1536 in 7 years, we can infer that the interest accrued over the 4-year difference (7 years - 3 years) is 1536 - 1344 = 192.

So, we have I = 192, T = 4. We are asked to find the principal sum (P) and we know that the rate of interest (R) is unchanged.

We can rearrange the simple interest formula to solve for P:

P = I / (RT)

However, we don't know the rate of interest (R). But we can find it from the first condition, where the sum becomes 1344 in 3 years.

Let's assume the principal is P and the rate of interest is R. After 3 years, the sum (principal + interest) becomes 1344. So, we can write:

P + PRT = 1344

Substituting P = 192 / (4R) into the equation, we get:

192 / (4R) + 192 = 1344

Solving this equation for R, we get R = 0.04.

Now, we can substitute R = 0.04 into the equation P = I / (RT) to find the principal:

P = 192 / (4 * 0.04) = 1200

So, the principal sum is Rs. 1200. But this is not in the options. It seems there might be a mistake in the problem or the options provided.