RRB NTPC - Simple Interest

  • 1. A man borrowed some amount, after 3 years he paid Rs.10,400/- with 10% interest, then how much Amount he borrowed? 
   A.) Rs.7000/-
   B.) Rs.8000/-
   C.) Rs.9000/-
   D.) Rs.1000/-

Answer: Option 'B'

principal P = ? 
Rate of interest R = 10% 
Time T = 3 years 
Accumulated Amount A = Rs.10400/- 
A = P + I 
A = P + PTR/100 
A = P(1+ TR/100) 
Rs.10400/- = P [1 + 3*10/100] 
Rs.10400/- = P [1/1 + 3/10] 
Rs.10400/- = P [10+3/10] = P[13/10] 
Rs.10400/- = P * 13/10 
==> P = Rs.104000/13 
==> P = Rs.8000/- 

  • 2. A man took some money for borrowed, for 3 years the total will be Rs.4000 and 5 years it will be Rs.5000/-. Then how much amount he borrowed? 
   A.) Rs.500/-
   B.) Rs.1500/-
   C.) Rs.2500/-
   D.) Rs.1000/-

Answer: Option 'C'

3 years --------> Rs.4000/- 
5 years --------> Rs.5000/- 
~                    ~
------------------------------  
2 years ----> Rs.1000/- 
1 year  -----> Rs.500/-  
3 years × Rs.500/- = Rs.1500/- 
P = Rs.4000/- - Rs.1500/- = Rs.2500/- 
P = Rs.2500/-

  • 3. A man took some money for borrowed, for 2 years the total will be Rs.9000/- and 5 years it will be13, Rs.500/-. Then how much amount he borrowed? 
   A.) Rs.4500/-
   B.) Rs.6000/-
   C.) Rs.5000/-
   D.) Rs.5500/-

Answer: Option 'B'

2 years --------> Rs.9000/- 
5 years --------> Rs.13500/- 
~                 ~
-----------------------------  
3 years ----> Rs.4500/- 
1 year -----> Rs.1500/-  
2years × Rs.1500/- = Rs.3300/- 
P = Rs.9000/- - Rs.30000/- = Rs.6000/- 
P = Rs.6000/- 

  • 4. A person took some amount with some interest for 1 years, but increase the interest for 2%, he paid Rs.60/- extra, then how much amount he took? 
   A.) Rs.3000/-
   B.) Rs.4000/-
   C.) Rs.2900/-
   D.) Rs.2000/-

Answer: Option 'A'

Only 1 year = 60/1 = 60 
Rate of Interest = 2% 
100/2% × 60 = Rs.3000/- 
P = Rs.3000/- 

  • 5. A person took some amount with some interest for 2 years, but increase the interest for 1%, he paid Rs.120/- extra, then how much amount he took?
   A.) Rs.5500/-
   B.) Rs.6000/-
   C.) Rs.4000/-
   D.) Rs.7000/-

Answer: Option 'B'

2 years = Rs.120/- 
year = 120/2 
Rate of Interest = 1% 
100/1% × 120/2 = Rs.6000/- 
P = Rs.6000/- 

  • 6. A person took some amount with some interest for 3 years, but increase the interest will be increase From 7% to 9%. He paid Rs. 240 extra, then howmuch amount he took? 
   A.) Rs.7000/-
   B.) Rs.4000/-
   C.) Rs.5500/-
   D.) Rs.6000/-

Answer: Option 'B'

2% ------> Rs.240/- 
3 years = Rs.240/- 
1 year = 240/3 = Rs.80/- 
100/2% × 80 = Rs.4000/- 
P = Rs.4000/- 

  • 7. A borrow took by a man, for every 5 years it will be doubled, then what is the rate of the interest? 
   A.) 15%
   B.) 20%
   C.) 22%
   D.) 23%

Answer: Option 'B'

P = 1 , I = 1 , T = 5years R = ? 
I = PTR/100 
1 = 1×5×R/100 
R = 20% 

  • 8. A borrow took by a man, for every 8 years it will be 3 times, then what is the rate of the interest?
   A.) 15%
   B.) 20%
   C.) 25%
   D.) 28%

Answer: Option 'C'

P = 1 , I = 2 , T = 8years R = ? 
I = PTR/100 
2 = 1×8×R/100 
R = 25% 

  • 9. A borrow took by a man, for every 12 years it will be 5 times, then what is the rate of the interest?
   A.) 33 1/3%
   B.) 18 1/3%
   C.) 33 2/3%
   D.) 34%

Answer: Option 'A'

P = 1 , I = 4 , T = 12years R = ? 
I = PTR/100 
4 = 1×12×R/100 
R = 33 1/3% 

  • 10. A borrow taken by a man, for every 5 years it will be doubled, then how much time it will be taken 
   A.) 12years
   B.) 15years
   C.) 16years
   D.) 13years

Answer: Option 'B'

(R)1% ------> 5 years 
3/1% × 5 = 15 years 
Answer = 15 years 

  • 11. The borrow taken by a man, for every 6 years it will be 3 times, then how much time it will be taken For 8 times: 
   A.) 20 years
   B.) 21 years
   C.) 22 years
   D.) 25 years

Answer: Option 'B'

(R)2% ------> 6 years 
7/2% × 6 = 21 years 
Answer = 21 years 

  • 12. An employ sell a t.v for Rs.9000/- with 10% simple interest for 5 years on an installment basis. Then How much amount he paid for each installment? 
   A.) Rs.1200/-
   B.) Rs.1500/-
   C.) Rs.1400/-
   D.) Rs.1350/-

Answer: Option 'B'

Instalment = 100 × P/100 × T+T × (T - 1)R/2 
= 100 × 9000/100 × 5+5 × (5-1)10/2 
= 100 × 9000/6000 = Rs.1500/- 

  • 13. Find simple interest on Rs.5000/- at 12% p.a, for 2 years? 
   A.) Rs.1300/-
   B.) Rs.1400/-
   C.) Rs.1200/-
   D.) Rs.1000/-

Answer: Option 'C'

P = Rs.5000/- 
T = 2 years 
R = 12% 
I = PTR/100 
I = Rs.5000 × 2 × 12/100 = Rs.1200/- 

  • 14. Find simple interest on Rs.6000/- at 7 ½% p.a. for 3years? 
   A.) Rs.1250/-
   B.) Rs.1350/-
   C.) Rs.1200/-
   D.) Rs.1400/-

Answer: Option 'B'

P = Rs.6000/- 
T = 3 years 
R = 15/2% 
I = PTR/100 
I = (6000 × 3 × 15/2)/100 
I = 90 × 15 = Rs.1350/-

  • 15. Find the simple interest 0n Rs.3000/- at 5 1/3% p.a. for 2 ½ years? 
   A.) Rs.150/-
   B.) Rs.200/-
   C.) Rs.400/-
   D.) None of these

Answer: Option 'C'

P = Rs.3000/- 
T = 5/2 years 
R = 16/3% 
I = PTR/100 
I = (3000 × 5/2 × 16/3)/100 
I = 25 × 16 = Rs.400/-

  • 16. Find the simple interest on Rs.7300/- at 12% p.a. for the period from jan-2007 to 18- april-2007? 
   A.) 247.20
   B.) 247
   C.) 346
   D.) 347

Answer: Option 'A'

247.20

  • 17. Find simple interest on Rs.4000/- at 15% p.a. for 9months? 
   A.) Rs.350/-
   B.) Rs.450/-
   C.) Rs.125/-
   D.) Rs.450/-

Answer: Option 'D'

T = 9 months = 9/12 = 3/4 
P = Rs.4000/- , R = 15% 
I =(4000 × 3/4 × 15) /100 = 30 v 15 = Rs.450/- 
I = Rs.450/-

  • 18. Find simple interest on Rs.6000/- at 10% p.a. for 2years 3 months? 
   A.) Rs.1350/-
   B.) Rs.1250/-
   C.) Rs.2350/-
   D.) None of these

Answer: Option 'A'

2 years 3months = 27/12 = T 
P = Rs.6000/- 
R = 10% 
I = (6000 × 27/12 × 10)/100 = 27 × 50 
I = Rs.1350/-

  • 19. Find simple interest on Rs.5000/- at 12% p.a. for 73days? 
   A.) Rs.220/-
   B.) Rs.120/-
   C.) Rs.210/-
   D.) None of these

Answer: Option 'B'

73 days = 73/365 = T 
P = Rs.5000 
R = 12% 
I = (5000*73/365*12)/100 = 120/- 
I = Rs.120/- 

  • 20. Find the principle, interest on Rs.1200 at 8% p.a. for 2 years? 
   A.) Rs.6500/-
   B.) Rs.7500/-
   C.) Rs.5500/-
   D.) None of these

Answer: Option 'B'

P = ? 
T = 2 years 
R = 8% 
I = Rs.1200/- 
I = PTR/100 
P = 100I/TR 
P = (100 × 1200)/(2 × 8) 
P = Rs.7500/-

  • 21. Find the principle, interest on Rs.900/- at 6% p.a. for 3 years? 
   A.) Rs.5000/-
   B.) Rs.4500/-
   C.) Rs.3500/-
   D.) Rs.2200/-

Answer: Option 'A'

P = ? 
T = 3 years 
R = 6% 
I = Rs.900/- 
I = PTR/100 
P = 100I/TR 
P = (100 × 900)/(3 × 6) 
P = Rs.5000/- 

  • 22. In how many years will sum of Rs 4000 yield an interest of Rs.1080/- at 9% p.a? 
   A.) 1 year
   B.) 3 years
   C.) 4 years
   D.) 2 years

Answer: Option 'B'

P = Rs.4000/- 
T = ? 
R = 9% 
I = Rs.1080/- 
I = PTR/100 
T = I × 100/PR 
T = (1080 × 100)/(400 × 9) 
T = 3 years 

  • 23. In how many years will sum of Rs.6000/- yield an interest of Rs.1200/- at 8% p.a? 
   A.) 2 1/2 years
   B.) 2 years
   C.) 1 1/2 years
   D.) 3 years

Answer: Option 'A'

P = Rs.6000/- 
T = ? 
R = 8% 
I = Rs.1200/- 
I = PTR/100 
T = (I × 100)/PR 
T = (1200 × 100)/(6000 × 8) 
T = 5/2 ==> 2 1/2 years 

  • 24. At what rate of percent per annum will a sum of money double in 8 years? 
   A.) 13 ¼%
   B.) 12 ½%
   C.) 11 ½%
   D.) None of these

Answer: Option 'B'

Let principal be Rs P. Then, S.I = Rs P and Time = 8 years> 
Rate = (100 × S.I)/(P × T) = (100 × P/P × 8)% p.a 
= 25/2 % p.a = 12.5% p.a 

  • 25. Simple interest on a certain sum 16/25 of the sum. if both the rate of interest and time are same. then what is the rate of interest?
   A.) 12%
   B.) 10%
   C.) 8%
   D.) 13%

Answer: Option 'C'

Let the principal be Rs x. Then, S.I = Rs(16x/25) 
Let, rate = R% p.a 
and time = R yearss. Then, 
S.I = (P×T×R)/100 ==>16X/25 
= x×R×R/100 ==> R×R = 64 = 8
Hence,rate = 8% p.a and time = 8 years 

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