Question

Find the compound interest on rs 4000 for 9 months at 20 per annun when the interest is rockened yearly

Answer 1

Principal = Rs. 2000, Time = 9 months = 3 quarters.

Now, the rate is 40% per annum but the interest has to be paid 4 times a year, i.e., an interest of (40 / 4) % = 10% is applied every 3 months.

Thus, amount to be paid after 9 months = Rs. 2000 x (1 + 10 / 100)^ 3

= Rs. 2000 x 1.331 = Rs. 2662.

Answer 2

Answer:

Compound interest on rs 4000 for 9 months at 20 per annun is RS.$630.5$

Step-by-step explanation:

In this particular question use the concept that the compound interest is calculated as, C.I = A – P, where P = principal amount and A = amount after compound interest, so A is calculated as, A=P(1+r100)n, where r is the rate of interest in percentage, n is the time in years, so use these concepts to reach the solution of the question.

Given data:

Principal amount = 4000 Rs.

Rate of interest, r = 20% per annum.

For 9 months compounded monthly.

I.e. ($\frac{9}{12}$) years compounded annually.

Therefore, $n=\frac{3}{4}$Years.

Now as we know that the compound interest is calculated as, C.I = A – P, where P = principal amount and A = amount after compound interest, so A is calculated as, $A=P(1+r100)^{n}$, where r is the rate of interest in percentage, n is the time in years.

So,$A=4000(1+\frac{20}{100} )^\frac{3}{4}$

Now as we see that the power is in fraction, so we convert this power into integer by multiplying 12 and for this we have to divide the rate of interest by 12, so that overall no change.

I.e. $n=\frac{3}{4}=0.75$

And $r = \frac{20}{12} \\=2$

So that what he got at 20% interest per annum for 9 months compounded monthly, is same as he got at 2% interest per annum for 9 years compounded annually.

$A=4000(1+\frac{1}{20})^{3}$

Now simplify this we have,

$A=4000(\frac{21}{20})^{3}\\A=4000(1.05)^{3}\\A=4000(1.157625)\\A=4630.5$

So the compound interest is,

$C.I = A- P \\= 4630.5 - 4000 = 630.5$ Rs.

So this is the required answer.

Reference Link

• https://brainly.in/question/5050574
• https://brainly.in/question/13501077