At simple interest, an amount becomes Rs. 1120 in 4 years and Rs. 1200 in 5 years. The principal amount is equal to -

Correct option is A

Given:
- The amount becomes Rs. 1120 in 4 years.
- The amount becomes Rs. 1200 in 5 years.
Concept Used:
The simple interest formula is given by:

Where P is the principal amount, R is the rate of interest, and T is the time in years.
The difference in amounts for the additional year will give us the simple interest for 1 year:
{SI for 1 year} = 1200 - 1120 = Rs. 80
Now, using the formula for simple interest:

P × R = 8000 — (Equation 1)
Now, we know:
A = P + SI
For the first case (4 years):

Using: P×R=8000 from Equation 1:

Solution:
The principal amount is Rs. 800.