A sum of money invested at 8% per annum amounts to Rs.12122 in 2 year.what will it amount to in 2 year 8 months at 9% per annum ?

Answer:

As we know that SI = P x R x T /100 (Where P = Principal Amount, R = Rate of Interest and T = Time).

Let us assume that the principal amount be Rs. X.

Then the SI will be Rs (12122 - X)

Rate of interest = 8% and Time = 2 yrs.

So (12122 - X) = X * 8 * 2/100

(12122- X) = 16X/100

1212200 - 100X = 16X

-100X - 16X = -1212200

-116X = -1212200

X = -1212200/- 116 = 10450.

So the Principal amount is equal to Rs. 10450.

Now the second part of the problem:

SI = PxRxT/100 (Where P = Rs 10450, R = 9% and T = 2yrs 8 Months = 2 Yrs 8/12 = 8/3 Yrs)

SI = 10450x 9 x 8/3/100= 250800/100 = Rs. 2508.

So the amount will be Rs. (10450 + 2508) = Rs. 12958.

**Ans: Rs. 12958.**