7. A farmer takes a loan of ₹8400 at a simple interest rate of [tex]\(7 \frac{1}{2} \%\)[/tex] per annum. After how much time will he have to pay ₹10,920 to clear the debt?



Answer :

Certainly! Let's solve this step-by-step.

1. Identify the given values:
- Principal (P): The initial amount of the loan is ₹8400.
- Final Amount (A): The amount to be paid to clear the debt is ₹10920.
- Rate of Interest (R): The simple interest rate is [tex]\(7 \frac{1}{2} \%\)[/tex] per annum, which can be written as 7.5%.

2. Convert the percentage to decimal form:
- [tex]\( R = 7.5 \% = \frac{7.5}{100} = 0.075 \)[/tex].

3. Recall the formula for the final amount in terms of simple interest:
[tex]\[ A = P + SI \][/tex]
where [tex]\( SI \)[/tex] is the simple interest. The formula for simple interest is:
[tex]\[ SI = P \times R \times T \][/tex]
Plugging in the simple interest formula into the final amount formula:
[tex]\[ A = P + (P \times R \times T) \][/tex]
[tex]\[ A = P(1 + R \times T) \][/tex]

4. Rearrange the formula to solve for time (T):
[tex]\[ A = P(1 + R \times T) \][/tex]
[tex]\[ \frac{A}{P} = 1 + R \times T \][/tex]

Simplify to isolate [tex]\(T\)[/tex]:
[tex]\[ \frac{A}{P} - 1 = R \times T \][/tex]
[tex]\[ T = \frac{\frac{A}{P} - 1}{R} \][/tex]

5. Substitute the values [tex]\(A = 10920\)[/tex], [tex]\(P = 8400\)[/tex], and [tex]\(R = 0.075\)[/tex] into the formula:
[tex]\[ T = \frac{\frac{10920}{8400} - 1}{0.075} \][/tex]

6. Calculate the intermediate steps:
[tex]\[ \frac{10920}{8400} = 1.3 \][/tex]
[tex]\[ T = \frac{1.3 - 1}{0.075} \][/tex]
[tex]\[ T = \frac{0.3}{0.075} \][/tex]

7. Finally, compute the value of [tex]\(T\)[/tex]:
[tex]\[ T = \frac{0.3}{0.075} = 4 \][/tex]

So, the farmer will have to pay ₹10920 to clear the debt after 4 years.