A sum of money amounts to 5200 Rs. in 5 years and to 5680 Rs. in 7 years at simple interest. The rate of interest per annum is :
A sum of money amounts to 5200 Rs. in 5 years and to 5680 Rs. in 7 years at simple interest. The rate of interest per annum is :
[A]3%
[B]4%
[C]5%
[D]6%
6%
P + SI 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 years = 240
∴ From equation (I),
P + 5 
Hence option [D] is correct answer.
