Simple Interest- Aptitude Questions and Answers

Let Principal = P, Rate = R% per annum, Time = n years.
Simple Interest (SI) = (P*R*T )/100

money doubles in 10 years then, 2P=P+(P*R*10 )/100
P=(P*R )/10
R=10

it become four times at the same rate then, 4P=P+(P*10*T )/100
3P=(P*T )/10
So, T=30

A = P(1 + rt/100)
P = principal
r = rate in %
t = time in years

A principle becomes twice in 5 years, that is
A= 2P, T=5 ,R=?
2P= P + PR * 5/100
2P-P = PR/20
P= PR/20
R= 20
now when the money 10 times, that is
A= 10P , R= 20 , T=?
10P = P + PRT/100 = P + P * 20 * T /100
10P-P = PT/5
9P = PT/5
T= 45
After 45 years the money becomes 10 times

Simple Interest (SI) = (P*R*T )/100
Amount, A = P + SI = P + (P*R*T)/100

Let the Orignal amount is P then ,R=7 and T= 15/2 years
18300 = P +[P* 7* (15/2) /100 ]
18300 = P + [ (P* 7* 15) / 200 ]
18300 = P + [ 21*P / 40 ]
61*P=18300 * 40
P=300*40
P=12000
Hence the Amount was 12000

Let Principal = P, Rate = R% per annum, Time = n years.
Simple Interest (SI) = (P*R*T )/100
Amount =P + (P*R*T )/100

Thus, 900 = P + (P*5*4 )/100
⇒ 900 = 6*P / 5
⇒ P = ( 900 x 5) /6
= Rs 750

Let Principal = P, Rate = R% per annum, Time = n years.
Simple Interest (SI) = (P*R*T )/100

Amount =P + (P*R*T )/100
Thus, 2P =P + (P*R*8 )/100
⇒ P= P*R*8 / 100
⇒ R = 100 /8
So, R=12.5%

Let Principal = P, Rate = R% per annum, Time = n years.
Simple Interest (SI) = (P*R*T )/100

S.I. for 1 year = Rs. (783 - 702) = Rs 81
S.I. for 2 years = Rs. (81 x 2) = Rs. 162
Then, Sum P = Rs. (702 - 162) = Rs. 540
So, Required rate R =(100 x SI) / (P x T) = (100 x 162) / (540 x 2) % = 15%

Let Principal = P, Rate = R% per annum, Time = n years.
Simple Interest (SI) = (P*R*T )/100

Then, Rate R = (SI x 100) / (P*T)
= (800 x 100) / (8000 x 2)
= 5%

Let Principal = P, Rate = R% per annum, Time = n years.
Simple Interest (SI) = (P*R*T )/100

Then, SI = 26350 - 21250 = 5100
R= (SI x 100) / (P * T)
= (5100 x 100) / (21250 x 6)
So, Rate R= 4%

Let Principal = P, Rate = R% per annum, Time = n years.
Simple Interest (SI) = (P*R*T )/100

Let, Principle lent out in two parts as x and 3900-x
Then As given,

x * 10* 5= (3900-x) * 9 * 6
25x = 3900*27 - 27x
52x=3900*27
x=2025

other part is x=2025
other part is 3900-x = 3900-2015 =>1875

Simple Interest (SI) = (P*R*T )/100
Amount, A = P + SI = P + (P*R*T)/100

Let the Orignal amount is P then ,
889 = P +( P* 9* 3)/100
127*P=889*100
P=88900/127
P=700
Hence the Amount was 700

Let the sum invested in Scheme A be Rs. x , And that in Scheme B be Rs. (13900 - x).
Then, [(x * 14 * 2) / 100] + {[(13900 - x) * 11 * 2] / 100 } = 3508
(28x / 100) + [(13900 - x) * 22] / 100 = 3508
28x + [(13900 - x) * 22] = 3508 * 100
28x + [(13900 - x) * 22] = 350800
28x + 305800 – 22x = 350800
28x – 22x = 350800 – 305800
6x = 45000
x = 7500
So, sum invested in Scheme B = Rs. (13900 – 7500) = Rs. 6400

Let the amount is X

As is given, (X*7*4 / 100) + (X*5*4 / 100) =960
28*X/100 + 20*X/100= 960
X=960*100 / 48 =2000

SI = 2641.20 - 1860 = 781.20

781.20 = (1860* 12* time) / 100
Time = 78120 / (1860* 12) =42 / 12 =7 / 2

Let the amount is X Then, after 4 years SI =770 - X

(770 - X) = (X* 10* 4) / 100
(770 - X) = X*2 / 5
2*X = 3850 - 5*X
7*X = 3850
X = 550

SI from scheme A = P*10*2 /100 =P/5
Amount received from scheme A =P + P/5 = 6P/5

Now, SI from scheme B= (6P/2)*12*5 /100 = 18P/25

According to the question, 18P/25 - P/5 = 1300
13P/25=1300
P=2500

Let the sum is p , rate r and time t , then simple interest = p*r*t /100
As is given
p*(r+3)*4/100 - p*r*4 /100 =720

p*4*(r+3 - r) = 720*100

p*12 = 72000

p= 6000

Let the sum is x
as given, (x*3*6)/100 +(x*8*5)/100 +(x*10*2)/100 =1560
18x + 40x + 20x =156000
78x =156000
x =2000
Hence sum is 2000