## Simple interest

1. The sum required to earn a monthly interest of Rs 400 at 10 % per annum at simple interest is
1. Rs 2000
2. Rs 12000
3. Rs 24000
4. Rs 48000
1. Simple Interest =(Principal × Rate × Time)/100

##### Correct Option: D

Total interest needed in a year = Rs 400 × 12
= Rs 4800
Principal = (100 × SI)/R × T
where, R = Rate
T = Time
SI= Simple Interest

Report

1. In what time will the simple interest on Rs 400 at 10% per annum be the same as the simple interest on Rs 1000 for 4 year at 4 % per annum?
1. 2 yrs
2. 3 yrs
3. 4 yrs
4. 6 yrs
1. Simple Interest = (Principal × Rate × Time)/100

##### Correct Option: C

Here , P= Rs 1000
T= 4 yrs
R= 4 %
where, P= Principal
T= Time
R= Rate
Since , Simple Interest on Rs 1000=(1000 × 4 × 4)/100
= Rs 160

now, simple interest=Rs 160
P = Rs 400
R = 10 %
then, T=(100 × SI)/P × R
= (100 × 160)/(400 × 10)
= 4 yr

Report

1. At what rate percent per annum will a sum of money double in 8 yr?
1. 12 %
2. 12.5 %
3. 13 %
4. 15 %
1. Amount A = 2 × P
where , P = Principal

Rate R = (100 × SI)/(P × T)
where , SI= Simple Interest
T= Time

##### Correct Option: B

Let Sum = P, Then SI=P
As Amount A = 2 × P
where , P = Principal

Rate R = (100 × SI)/(P × T)
= (100 × P)/(P × 8) %
= 12.5 %
where , SI= Simple Interest
T= Time

Report

1. Find the sum of money will amount to Rs 900 in 4 years at 5 % per annum on simple interest?
1. Rs 750
2. Rs 650
3. Rs 500
4. Rs 550
1. Let the sum of money be Rs y
So Amount = y +[( y x 5 x 4 )/100]

##### Correct Option: A

Let the sum of money be Rs y
So Amount = y +[( y x 5 x 4 )/100]
But Amount = Rs 900
⇒ 900 = y +(20y)/100
⇒ 900 = 6y / 5
⇒ y = ( 900 x 5) /6
= Rs 750

Report

1. If a certain sum is doubled in 8 yr on simple interest, in how many year will it be four times?
1. 24 yr
2. 16 yr
3. 32 yr
4. 12 yr
1. Let the sum be Rs 'y' , so amount = 2y
Simple interest =Rs y
Let R be the rate of interest,
R= (100 x SI)/(P x T)
where SI= Simple Interest
P = Principal
T = Time

##### Correct Option: A

Let the sum be Rs 'y' , so amount = 2y
Simple interest =Rs y
Let R be the rate of interest,
R= (100 x SI)/(P x T) = (100 x y) / (y x 8) = 12.5 %
where SI= Simple Interest
P = Principal
T = Time

now, the needed amount = Rs 4y
since SI = Rs (4x-x)= Rs 3y
since T= (100 x SI)/(P x R)
= (100 x 3y )/(y x 125)= 24 yr

Report