Question

On 12 february 2009,sally invested $2000 in a bank and received an amount or $2040 on 23 june 2009.calculate the simple interest rate offered by the bank

Answer 1

You will have to count the number of days from Feb 12 to June 23, I will leave that up to you and label it 'days'

in I = PRT, your I = 40, R = ??, T = days/365 , P = 2000

40 = 2000(R)(days/365)
R = 40(365)/(2000(days)) =

your R will be a decimal, I will assume you know how to change that into a percent.

Here is a "between dates" calculator. Notice it counts the first day, but not the last day. Check how your text wants you do it it.
https://www.timeanddate.com/date/durationresult.html?m1=02&d1=12&y1=2017&m2=06&d2=23&y2=2017