If the simple interest on a sum of money for 2 years at 5% per annum is Rs.50, what will be the compound interest on same values

Answer: Option B

Explanation:

S.I. on Rs 800 for 1 year = 40

Rate = (100*40)/(800*1) = 5%

Answer: Option D

Explanation:

Difference between C.I and S.I for 2 years = 36.30
S.I. for one year = 330.
S.I. on Rs 330 for one year = 36.30

So R% = \frac{100*36.30}{330*1} = 11%

Answer: Option A

Explanation:

As per question we need something like following

$$\begin{aligned} P(1+\frac{R}{100})^n > 2P \\ (1+\frac{20}{100})^n > 2 \\ (\frac{6}{5})^n > 2 \\ \frac{6}{5} \times \frac{6}{5} \times \frac{6}{5}\times\frac{6}{5} > 2 \end{aligned}$$

So answer is 4 years

Answer: Option C

Explanation:

$$\begin{aligned} S.I. = \frac{1000*10*4}{100} = 400 \\ C.I. = [1000(1+\frac{10}{100})^4 - 1000] \\ = 464.10 \end{aligned}$$

So difference between simple interest and compound interest will be 464.10 - 400 = 64.10

Answer: Option B

Explanation:

In this type of question we apply formula
$$\begin{aligned} Amount = \frac{P}{(1+\frac{R}{100})^n} \\ Amount = \frac{169}{(1+\frac{4}{100})^2} \\ Amount = \frac{169 * 25 * 25}{26*26} \\ Amount = 156.25 \end{aligned}$$