P = Principal
R = Rate of Interest
N = Number of years
SI(Simple Interest) = P x N x R/100
CI(Compound Interest) = P(1 + R/100)n
(1) Find the simple interest of Rs.14000 at 10% per annum for 3 months ?Answer: Option [B]
The formula to calculate simple interest is :
SI=(P x T x R)/100
In the given question Principal(P)=Rs. 14000, Time(T)=(3/12)yr. and Rate of interest(R)=10%
So, SI=(14000 x 1/4 x 10)/100
=SI= Rs. 350
Answer: Option [A]
Let the initial amount be Rs. 100
It will be double. That means Rs. 200
The simple will be Rs. (200-100)= Rs. 100
We can calculate the time from the formula given below :
T=(SIx100)/(PxR)
T=(100x100)/(100x7)
T=14.28 Yr
Answer: Option [B]
Let the initial amount be Rs.100
After 2 Yrs. the sum will be Rs.140
Calculated SI is Rs.40
Now we can calculate the rate of interest from the formula given below :
R=(SIx100)/(PxT)
R=(40x100)/(100x2)
R=20%
Answer: Option [B]
P = ₹ 16500
R% = 14% per annum
n = 3years
A = p(1+R/100)n
A = 16500(1+14/100)2
A = ₹ (16500 x 114/100 x 114/100)
A = ₹ 21443.4
CI = ₹ (A - P)
CI = ₹ (21443.40-16500.00)
CI = ₹ 4943.40
Answer: Option [C]
SI = ₹ 15300
P = ₹ 45000
T = 4 yrs.
R% = (SIx100/PxT)
R% = (15300x100/45000x4)
R% = 8.5% per annum
Now we can calculate the Compound interest from above data.
CI(compound interest) = A-P
Now we calculate A = P(1+R/100)n
A = 45000(1+8.5/100)4
A = ₹ 62363
CI = A - P
CI = ₹ (62363 - 45000)
₹ 17363