# Simple Interest

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%

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

26.

If the simple interest on Rs. 1120 for 2 years is Rs.8000/-, what is the rate of interest percent per annum?

A.) 4%
B.) 7%
C.) 8%
D.) 5%

I = Rs.1120/-
T = 2 years
P = Rs.8000/-
R = ?
S.I = (P×T×R/100)
R = (S.I×100)/(P×T)
R = (1120×100)/(8000×2)
R = 56/8 = 7%

27.

If the simple interest on Rs.400 for 3 years is Rs.4000/-, what is the rate of interest percent per annum?

A.) 4 1/3%
B.) 3 1/4%
C.) 3 1/3%
D.) None of these

I = Rs.400/-
T = 3 years
P = Rs.4000/-
R = ?
S.I = (P×T×R/100)
R = (S.I×100)/(P×T)
R = (400×100)/(4000×3)
R = 10/3 = 3 1/3%