Mr. Cheung set up an account in an investment company at the beginning of this year. He makes an investment on the first day of each month. He invested $4000 in the first month and increased the monthly investment by 5% in each subsequent month. (a) How much will he invest in the last month of this year?

(b) Find the total amount that he will invest in this year.

(c) If the monthly return on his investment is 3%, find the total amount that he will get at the end of the year.

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