please show work on excel. will upvote

Sammie's Lemonade is a small business that specializes in producing lemonade and selling it over the Internet. The firm opens only for few month around the summer time. This year Sammie's Lemonade was in business only in June, July, and August. In June, the firm bought all the required supplies for the production. The whole bill came up to be $21,000 : half of it was paid immediately and another half - in August. In total, the firm produced 3,000 bottles, meaning that the cost of one bottle was $7. All the production of lemonade happened in June, while the sales occurred in July and August. Sammie's Lemonade sold 1,500 bottles of lemonade in July and 1,500 bottles in August. Each bottle was sold for $10. All customers paid for their purchases in August. The corporate tax rate is 30%. For simplicity, assume that all the cash flows occur at the end of the month. (a) What is the change in net working capital in every month? (b) What is the firm's NOPAT in every month? (c) What is the firm's free cash flows in every month? (d) If the monthly discount rate is 5\%, what is the net present value of the firm's FCFs in the end of June