## 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/-

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/-

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/-

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/-

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/-

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/-

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%

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%

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%

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

(R)1% ------> 5 years
3/1% × 5 = 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

(R)2% ------> 6 years
7/2% × 6 = 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/-

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/-

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/-

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

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

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/-

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

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

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

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/-

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

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

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

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%