A sum of money amounts to Rs.5,200 in 5 years and to Rs.5,680 in 7 years at simple interest. The rate of interest per annum is
1). 3%
2). 4%
3). 5%
4). 6%
I think it may be right answer
P + S.I. for 5 years = 5200 ..(i)
P + SI for 7 years = 5680 ...(ii)
On subtracting equation (i )
from (ii),
SI for 2 years = 480
SI for 1 year = 240
From equation (i),
P + 5 × 240 = 5200
P = 5200 – 1200 = 4000
R = $\frac{S.I\times100}{T\times P}$
= 6%