A student takes on $50,000 of debt in August 2 of 2020 at an annual interest rate of 8%. She makes no payments while in school. On November 2, 2024 she prepares to start repaying her debt on a 15-year repayment cycle and the payment size is calculated. The first payment is made in December 2, 2024, the last one on November 2, 2039. On December 2, 2024 she finds herself with an extra $500, which she pays (in addition to the regular payment) toward reducing her debt.

I need someone to help me with BOTH of these please!

a.) Assuming she makes standard payments thereafter, what month (and year) will the final payments be made?

b.) How much interest did she save herself by making the payment in 2c? Round down to the nearest $10.

Someone answered this incorrectly the first time I posted a few days ago so if you are them please don't reanswer.

Monthly payment per $1,000 initially borrowed Interest rate 15-year loan 30-year loan $7.40 $4.77 4.0% $5.07 4.5% $7.65 5.0% $7.91 $5.37 $8.17 $5.68 5.5% $6.00 6.0% $8.44 $8.71 $6.32 6.5% $6.65 7.0% $8.99 7.5% $9.27 $6.99 8.0% $9.56 $7.34 $9.85 $7.69 8.5% 9.0% $10.14 $8.05 $10.44 $8.41 9.5% $8.77 10.0% $10.75 10.5% $11.05 $9.15 11.0% $11.36 $9.52 11.5% $11.68 $9.90 12.0% $12.01 $10.29