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/-

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 

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%

Answer: Option 'B'

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

Answer: Option 'C'

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% 

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