Question 728355
The interest he needs to pay back is 30 dollars (the difference in the amount he borrows and has to pay back).


I = Prt


30 = 4000*r*(2/12)


30 = 666.667r


30/666.667 = r


r = 0.04499998


r = 0.045 (rounded to the nearest thousandth)


r = <font color="red">4.5%</font>