Answer:
Rate of simple interest charge by bank is 9.125
Explanation:
Given as :
The principal = Rs 8000
The amount paid = Rs 8640
The time period = 320 days
Let the rate of simple interest = R
So from simple interest method
Simple Interest =
![(Principal* rate* Time)/(100)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/ess4xes490h968mo2sjk9cls9mti3axtpa.png)
∵, Interest = Amount - principal
Or, Interest = Rs 8640 - Rs 8000 = Rs 640
∴ Rs 640 =
![(8000* rate* (320)/(365))/(100)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/pz58ln40qvc1xe02kumyr5odvho84e11di.png)
Or, 64000 × 365 = 8000 × 320 × rate
Or 23360000 = 2560000 × rate
So, rate =
![(23360000)/(2560000)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/tzbkpnotvu8xl4q9wh5krzm3jl1a2m5jta.png)
∴ Rate = 9.125
I.e rate of simple interest charge by bank is 9.125 Answer