Shiing Shen Chern's credit card company determines his minimum monthly payment by adding all new interest

to $1\%$ of the outstanding principal. The credit card company charges an interest rate of $0\mathrm{.}036604\%$ per day. On

March $20,$ Shiing uses his credit card to purchase airline tickets for his family for $$2100.$ He makes no other

purchases during March. Use the given information and the rule that minimum payments are rounded up to the

nearest dollar to answer parts a and $b$ below.

a$)$ Assuming Shiing had no new interest, determine Shiing's minimum payment due on April $1,$ his billing date.

Shiing's minimum payment due on April $1$ is $

b$)$ On April $1,$ instead of making the minimum payment, Shiing makes a payment of $$400.$ Assuming there are no

additional charges or cash advances, determine Shiing's minimum payment due on May $1.$

Shiing's minimum payment due on May $1$ is $$.$