A certain sum amounts to Rs 13200 after 4 years and to Rs 16400 after 8 years at the same rate percent p.a. at simple interest. The simple interest (in Rs) on the same sum at 10% p.a. for 3 1/5 years will be :

Options
a) 4000
b) 3200
c) 2500
d) 3500

Solution

As per question
P = Principle or sum
R = Rate
T = Time
Interest for 4 year = 16400 – 13200 = 3200
Ist 4 year interest also will be 3200 Rs.
Principle or sum (P)= 13200 – 3200 = 10000
Time (t) =
Rate of Interest (r) = 10%
Simple interest (S.I) =
S.I =
S.I = 200 x 16 = 3200

Ans: 3200