- There is 50% increase in an amount in 5 years at simple interest. What will be the compound interest of Rs. 10,000 after 2 years at the same rate?
Rs2450Rs2100Rs1855Rs2200NoneOption B

Solution:

Let principal be Rs100. rate r.

50% increase in amount says SI=50.

(100*5*r /100) =50

r=10%.

CA=P[(1+r/100)^{2}] =10,000*[(1+10/100)^{2}] =10,000*11/10*11/10

=12100.

CI=Rs2100. - A lent Rs. 4000 to B for 3 years and Rs. 5000 to C for 4 years on simple interest at the same rate of interest and received Rs. 3200 in total from both as interest. The rate of interest per annum is:
6%12%15%10%NoneOption D

Solution:

Let the rate be r%

(4000*3*r/100) + (5000*4*r/100) =3200

120r+200r=3200

320r=3200

r=10%.

- What is the compound interest per annum for a sum of Rs. 1500 in 2 years at 5% rate?
Rs185Rs143.25Rs153.75Rs102.05NoneOption C

Solution:

CI=1500*(1+5/100)2 -1500

=1500*21/20*21/20 -1500

=1653.75-1500

=Rs153.75.

- The simple interest accrued on an amount of Rs. 22,500 at the end of four years is Rs. 10,800. What should be the compound interest accrued on the same amount at the same rate of interest at the end of two years?
Rs4566Rs4852Rs5724Rs4375NoneOption C

Solution:

r=10800*100 /22500*4

r=12%

Then CI=10,800*[(1+12/100)^{2-1] =22500 {112/100*112/100 -1} =9*28*112 -22500 =28224-22500 =Rs5724. } - A person borrows Rs. 8000 for 2 years at 6% p.a. simple interest. He immediately lends it to another person at 7 1/2 p.a for 2 years. Find his gain in the transaction per year.
Rs180Rs120Rs90Rs150NoneOption B

Solution:

Gain in 2 years =(8000*15/2*2/100) –(8000*6*2)/100

=1200-960

=240.

Gain for 1 year=240/2

=Rs120.

- If the simple interest on a certain sum of money is 4/25 of the sum and the rate per cent equals the number years, then the rate of interest per annum is
8%10%4%6%NoneOption C

Solution:

Let the principal be x and rate be r%

Then SI=4/25x

n=r

r=(100*4/25x)/rx

r^{2}=400/25

r=20/5

=4%.

- Mr. X invested Rs. 20,000 with rate of interest at 10% per annum. The interest was compounded half yearly for first year and in the next year it was compounded yearly. What will be the total interest earned at the end of two years?
Rs4255Rs5880.6Rs4230.5Rs5600NoneOption A

Solution:

For 1st year Compounded halfyearly

amount=20000*(1+5/100)2

=50*21*21

=Rs22050.

For 2nd year Compounded halfyearly.

Then amount=22050* (1+10/100)

=Rs24255

Interest=24255-20000

=Rs4255.

- A sum was invested at simple interest at a certain interest for 3 years. It would have fetched Rs. 720 more had it been invested at 5% higher rate. What was the sum?
Rs4800Rs3700Rs4560Rs3950NoneOption A

Solution:

[(p*3*(r+5)/100] – (p*3*r)/100) =720

3pr/100+15p/100-3pr/100=720

15p=720*100

p=Rs4800.

- A man lends a certain sum of money at simple interest. Rate of interest for first one and half years is 4% per annum, for next 6 months is 5% per annum and after that 8% per annum. If he received Rs. 8737.5 at the end of 3 years, what was his principal?
Rs6850Rs7200Rs7380Rs7500NoneOption D

Solution:

Let the principal be x

x+ (x*4*3)/(100*2) + (x*5*1)/(100*2) +(x*8*1)/100 =8737.5

x+12x/200+5x/200+8x/100=8737.5

233x=8737.5*200

x=Rs7500.

- Find the difference between the simple interest and the compound interest at 10% per annum for 3 years on principal of Rs. 5000.
Rs230Rs190Rs155Rs210NoneOption C

Solution:

SI-CI=[Pr^{2}*(300+r)]/100^{3}

=(5000*100*310 )/ (100*100*100)

=31*5

=Rs155.