Hello, thank you for taking the time to post your question!
The underlying formula that you want to use to solve here is
Id = P x d x t
We’re given in the information in the question that P = 2900, d = 0.11, and Id = 638
Meaning that the equation becomes
638 = 2900 x 0.11 x t
Solving that algebraically for the value of “t” gives
t = 638 / (2900 x 0.11)
t = 638/319
t = 2
so that means that it would take 2 years to pay it off for this scenario
I hope that helps get you moving in the right direction! Feel free to reach out if you have any additional questions beyond that :)