Shealeigh and Allison each spend X dollars to purchase annuities. Shealeigh buys a perpetuity-immediate, which makes annual payments of 50. Allison buys a 15-year annuity-immediate, also with annual payments. Allison 's first payment is 64, with each subsequent payment k% larger than the previous year's payment. Both annuities use an annual effective interest rate of k%. Calculate k.