A sum is being lent at 20 % per annum compound interest.what is the ratio of increase in amount of 4th year to 5th year?

Correct Answer: Rs.2522

Explanation:

Principal = Rs.16,000;

Time=9 months = 3 quarters;

Amount

=Rs.[16000x(1+5/100)³] =[16000x21/20x21/20x21/20]

= Rs.18522.

 

C.I

= Rs.(18522 - 16000)

= Rs.2522.

Correct Answer: 5400

Explanation:

Interest for 1 year is the same whether it's simple interest or the compound interest.

Now interest of third year = 8575 - 7350 = 1225; means principal for this interest is 7350 if comound interest is takenIf 7350 is the principal interest = 1225

if 100 is the principal interest =(1225/7350) * 100 = 50/3 %

When a thing increases for two successive times the overall increase on initial amount = a + b + (a * b)/100

Therefore overall interest for two years = 50/3 + 50/3 + [(50/3)*(50/3)]/100 = 325/9 %

Therefore amount after 2 years = 100 + 325/9 = 1225/9

If 1225/9 is the amount principal =100

if 7350 is the amount principal =(900/1225)*7350 =5400

So sum = 5400; Rate = 50/3 %

Correct Answer: Rs.1261

Explanation:

Clearly, Rate = 5% p.a .,

Time = 3 years

S.I =Rs.1200.

So,Principal

=Rs.(100 x 1200/3x5)

=Rs.8000.

 

Amount

=Rs.[8000 x (1+5/100)³]

=Rs(8000x21/20x21/20x21/20)

= Rs.9261

 

C.I

=Rs.(9261-8000)

=Rs.1261.

Correct Answer: Rs.8000

Explanation:

Compound Interest on P at 10% for 2 years when interest is compounded half-yearly

 

= P 1 + R 2 100 2 T - P = P 1 + 1 20 4 - P = P 21 20 4 - P

 

Simple Interest on P at 10% for 2 years =  P R T 100 = P × 10 × 2 100 = P 5

 

Given that difference between compound interest and simple interest = 124.05

  P * 21 20 4 - P - P 5 = 124 . 05

 

=> P 21 20 4 - 1 - 1 5 = 124 . 05

 P=8000

Correct Answer: 3430

Explanation:

Let each installment be Rs.x. Then, 

(P.W. of Rs.x due 1 year hence) + (P.W of Rs.x due 2 years hence) + (P.W of Rs. X due 3 years hence) = 7620.

 

x 1 + 50 3 x 100 + x 1 + 50 3 x 100 2 + x 1 + 50 3 x 100 3 = 7620

 

  6 x 7 + 36 x 49 + 216 x 343 = 7620

 

  294 x + 252 x + 216 x = 7620 x 343

 

 => x = 3430

 

 Amount of each installment = Rs.3430

Correct Answer: Rs.98.56

Explanation:

difference in C.I and S.I in 2years =Rs.32

S.I for 1year =Rs.400

S.I for Rs.400 for one year =Rs.32

rate=[100*32)/(400*1)%=8%

difference between in C.I and S.I for 3rd year

=S.I on Rs.832= Rs.(832*8*1)/100=Rs.66.56

Correct Answer: 3years

Explanation:

 

Let P = Rs. 100. Then, S.I. Rs. 60 and T = 6 years.

 

R= 100 * 60 100 * 6 =10% p.a

 

Now, P = Rs. 12000. T = 3 years and R = 10% p.a.

 

C.I= R s . 12000 * 1 + 10 100 3 - 1
       =Rs.3972

Correct Answer: 11%

Explanation:

Difference in C.I and S.I for 2 years

= Rs(696.30-660)

=Rs. 36.30.

 

S.I for one years = Rs330.

S.I on Rs.330 for 1 year =Rs. 36.30 

 

Rate

= (100x36.30/330x1)%

= 11%

Correct Answer: Rs. 1400

Explanation:

We know thatThe Difference between Compound Interest and Simple Interest for n years at R rate of interest is given by  C . I n - S . I n = P R 100 n

Here n = 2 years, R = 20%, C.I - S.I = 56

$$\begin{gathered} 56 = P 20 100 2 \\ = > P = 56 x 5 2 \\ = > P = 56 x 25 \\ = > P = Rs . 1400 \end{gathered}$$