I'm having the most trouble with part c and d. What does bp(basis points) tell us and how do I use them. Thanks!

1. RBN, Inc. has set its IPO price at $24 per share. It is offering 18,000,000 million shares in its IPO. The lead underwriter is to get a total spread of 600 bp (this includes the 50bp for expenses) and is allotted 6,000,000 shares. The rest of the selling group of investment banks (eight in all) split the remaining 12,000,000 shares evenly, and receive 375 bp for their selling efforts. Assume all shares are sold. How large is RBN's IPO? $432 m b. What are the proceeds to RBN from its IPO? $406.08 m c. How much does the lead underwriter net for the IPO? $15.12 m d. How much does each of the other eight investment banks receive for the IPO? $1.35 m a