Questions and Answers on Simple and Compound Interest

Let us assume the years as x

SI = \frac{P\times N\times R}{100}

Initial amount = 1500

Amount after simple interest = 15000

Therefore, interest = 15000 – 1500 = 13500

Taking time T as x

Thus, 13500 = \frac{1500\times x\times 15}{100}

1350000 = 22500x

x = 1350000/22500 = 60 Years

: Let us assume the rate of remaining amount as x

Remaining amount = 20000 – (4000 + 8000 + 2800) = 5200

Then, \frac{4000\times 8\times 1}{100} = 320

Similarly, \frac{8000\times 7.5\times 1}{100} = 600

Similarly, \frac{2800\times 8.5\times 1}{100} = 238

Given, 320 + 600 + 238 + \left (\frac{5200\times x\times 1}{100} \right )= \frac{20000\times 8.13\times 1}{100}

= 1158 + (52x) = 1660

= 52x = 1660 – 1158

52x = 502

x = 9.6

Therefore, the man will get 9.6% on Rs. 5200.

Let us assume the rate as r% per annum.

Then, \frac{7000\times r\times 2}{100} + \frac{5000\times r\times 4}{100}

140r + 200r = 3060

r = \frac{3060}{340} = 9

Rate = 9%.

Let us assume the rate as r%.

Given, new interest rate = 2r%.

Given, the rate for 1 year

And, new rate = 4 months or 1/3  year(s).

Therefore, 1725 * r * 1 / 100 + 1362.5 * 2r * 1 / 100*3 = 133.5

= (5175 + 2725)r = 133.5 * 300

= 7900r = 40050

r = 40050/7900 = 5.06

Therefore, the original rate = 5.06%

Amount = 100 * 5400  / 15 * 5

= 540000 / 75

= 7200

Let us assume the years as x

SI = PxNxR/100,

Initial amount = 1375

Amount after simple interest = 20000

Therefore, interest = 20000 – 1375 = 18625

Thus, 18625 = 1375 * x * 15 /100

1862500 = 20625x

x = 1862500/20625 = 90. 3 Years

Extra amount invested by a person (605 – 550)= Rs.55
so the additional interest he earned on F.D = Rs.55

The first year interest=550/2=275rs.

Rate of interest=55/275*100=20%

20% interest means the person received 20% of the amount he invested in the F.D.

Now clearly if in one fixed deposit his 20% of his investment= Rs.275,

So his total investment = 275/20*100=1375. Thus his total saving before investment=2*1375=2750 rs.

Simple interest for one year = (1954 - 1800) = 154.

Simple interest for 5 years = (154 x 5) = 770.

Principal amount = (1800 - 770) = 1030

The amount is calculated as P(1 + RT)

Here P = ?, R = 5% Per Annum, T = 4 Years, S.I = 5016.25

S.I = \frac{P\times R\times T}{100}

5016.25 = \frac{P\times 5\times 4}{100}

\frac{5016.25\times 100}{20} = P

P = 25081.25

Now calculating the amount

A = P(1 + RT)

A = 25081.25\left ( 1 + \frac{5}{100}4\right )

on solving the above equation we get,

A = Rs. 30,097.5

t= (SI×100) /PR

=>t = (1050×100)/(3500×6) = 5

Now, the rate of interest of rs. 1800 on rs. 4500 for 5 years be 'r'

So, r = (1800×100)/(4500×5) = 8%

T1 = 2, R1= 8%, T2=3 yr and R2 = 6%

Assume the value to be X.

Then, (X × 6 × 3)/100 − (X × 8 × 2)/100 = 30

=> 18X/100 – 16X/100 = 30

=> X = 1500 INR

Let us assume the rate as r%

Time as r years.

Then, (12000 x r x r) /100   = 4320

120r² = 4320

r² = 4320/120 = 36

r = 6.