Question

Find SI on 1507.25 at 5% per annum for a period from 3rd July to 19 November

Answer 1

Simple Interest: Interest is said to be simple if it is calculated on the original principle
throughout the loan period, irrespective of the length of the period, for which it is borrowed. It
is usually paid yearly, half-yearly or quarterly as agreed to between the parties.
Formulae: Amount = Principal + Interest
If simple interest is denoted by I, P principal, R the rate percent per annum, T the time
in years, then
v) The annual payment that will discharge a debt of Rs. A due in T years at the rate of
interest R% per annum is
vi) If a sum of money become 'n' times in t years at simple interest, the rate of
interest is given by
vii) Relationship between the principal (P) and the amount (A)
PROBLEMS
1. What is the interest on Rs.400 for 3 years at the rate of 6% per annum.
1) 65 2) 72 3) 80 4) 85
Ans: 2
Sol: Interest on Rs.100 for 1 year = Rs. 6
Interest on Re.1 for 1 year =
Interest on Rs.400 for one year =
400 6
100
×
6
100
100 amount P
100 RT
× = +
100(n 1)
T
−
100A
RT(T 1) 100T
2
⎛ ⎞ − + ⎜ ⎟ ⎝ ⎠
100 I iv) T P R
× = ×
100 I iii) R P T
× = ×
100 I ii) P R T
× = ×
PRT i) I 100
×