Suppose that Jack and Jill both have the same amount of money to invest. Jack chooses an account that earns i% simple interest. Jill chooses an account that earns j%(1). If they both still have the same amount after 1 year, what is the only way they can have that same amount after 2 years?

This has already been asked here but the answer given was wrong/incomplete. Please show work if you can. Thanks.