(200 + 200) * (201 * (1.005^540 - 1) =>
400 * 201 * (1.005^540 - 1) =>
1107909.0297478100810216503607318
x = 400
(400 + 200) * 201 * (1.005^540 - 1) =>
600 * 201 * (1.005^540 - 1) =>
1661863.5446217151215324755410977
2 accounts, each with 200 per month:
2 * 1107909.0297478100810216503607318 =>
2215818.0594956201620433007214636
b)
Once again, this depends on how we interpret the question
1 account, 200 total from Jason and Michelle
200 * 12 * 45 + 200 * 12 * 45 =>
400 * 540 =>
216000 in principal payments.
891909.02974781008102165036073181 in interest
1 account, 400 total from Jason and Michelle
(400 + 200) * 12 * 45 =>
600 * 540 =>
324000 in principal
1337863.5446217151215324755410977 in interest
2 accounts, 200 per month from each
432000 in principal
1783818.0594956201620433007214636 in interest
c)
Take the final amount and multiply it by (1 - 0.03)^45
1 account, 200 total: 281340.42810962343702497833740043
1 account, 400 total: 422010.64216443515553746750610064
2 accounts, 200 each: 562680.85621924687404995667480086