Use excel

Mr$.$ Van Trapp is $35$ years old today and has begun to plan for his retirement. He wants to set aside an equal amount at the end of each month in the next $25$ years so that he can retire at age $60.$ He expects to live to a maximum age of $80$ and wants to be able to get an after$-$tax payment of $$2,500$ per month from his account after retirement. His retirement account is expected to earn $10\%$ per annum $($with monthly compounding$)$ for the entire period of time. He has $$6,000$ in his savings account now, and also hopes to have $$20,000$ left at the end of age $80.$

Suppose Mr$.$ Van Trapp's company will deposit $$100$ into his retirement account each month as well.

A$.$ What is the pre$-$tax payment per month that Mr$.$ Van Trapp needs after retirement, assuming a tax rate of $15\%?$

B$.$ What is the amount of funds needed by Mr$.$ Van Trapp at the end of age $60$ so that he will be able to get an after$-$tax payment of $$2,500$ per month after retirement, and have $$20,000$ left at the end of age $80?$

C$.$ What is the amount of the monthly deposits that must be made by Mr$.$ Van Trapp before he retires?