Rs.100 doubled in 5 years when compounded annually. How many more years will it take to get another Rs.200 compound interest

Correct Answer: 8780.80

Explanation:

when interest is reckoned using compound interest, interest being compounded annually. The difference in the simple interest and compound interest for two years is on account of the interest paid on the first year's interest  Hence 12% of simple interest = 90 => simple interest =90/0.12 =750.

As the simple interest for a year = 750 @ 12% p.a., the principal =750/0.12 = Rs.6250.

If the principal is 6250, then the amount outstanding at the end of 3 years = 6250 + 3(simple interest on 6250) + 3 (interest on simple interest) + 1 (interest on interest on interest) = 6250 +3(750) + 3(90) + 1(10.80) = 8780.80.

Correct Answer: 4 years

Explanation:

P 1 + 20 100 n > 2P 

 

 

 

Now, (6/5 x 6/5 x 6/5 x 6/5) > 2.

 

 

 

So, n = 4 years.

Correct Answer: 5%

Explanation:

C.I =  P 1 + r 100 t - 1

 

594.5 =  5800 1 + r 100 2 - 1

  594 . 5 5800 + 1 = 1 + r 100 2

 

r 100 = 1 . 05 - 1 = 0 . 05 = > r = 5 % .

Correct Answer: Rs. 704

Explanation:

We know that,

$$\begin{gathered} S . I . = PTR 100 \\ ? P = S . I x 100 T x R \\ And also , \\ C . I = P 1 + R 100 n - 1 \end{gathered}$$

From given data, P = Rs. 8625

Now, C.I  =  $$\begin{gathered} 8625 1 + 4 100 2 - 1 \\ = 8625 26 25 2 - 1 \\ = 8625 676 625 - 1 \\ = 8625 x 51 625 \\ C . I = Rs . 703 . 80 \end{gathered}$$

Correct Answer: 1080

Explanation:

Let the sum be Rs. x. Then,

 

  C . I = x * 50 300 * 100 3 - x = 343 x 216 - x = 127 x 216 

 

? 127 x 216 = 1270 

 

x = 2160 

 

Thus, the sum is Rs. 2160

 

  S . I = R s . 2160 * 50 3 * 3 * 1 100 = R s 1080

Correct Answer: Rs.8820

Explanation:

 

Amount =  R s . 8000 * 1 + 5 100 2=Rs.8820

 

 

Correct Answer: 6.09%

Explanation:

Amount of Rs. 100 for 1 year

when compounded half-yearly = Rs.[100*(1+3/100)^2]=Rs.106.09

Effective rate=(106.09-100)%=6.09%

 

Correct Answer: Rs. 1901

Explanation:

P = Rs. 15225, n = 9 months = 3 quarters, R = 16% p.a. per quarter.

 

Amount =  15225 x 1 + 4 100 3

 

= (15225 x 26/25 x 26/25 x 26/25) = Rs. 17126.05

 

=> C.I. = 17126 - 15625 = Rs. 1901.05.

Correct Answer: 11 percent

Correct Answer: Rs.500

Explanation:

Let the sum be Rs. P.

Then,[p(1+10/100)2-p]=525

Sum =Rs.2500

S.I.= Rs.(2500*5*4)/100

= Rs. 500