Stipulating a fixed amount as profit in an investment

Q: I am running a business of supplies and transportation. One of my friends is interested to invest with me in a car. He wants to invest ten lac rupees for five years on a profit ratio of rs. 1500 per month. Is it permissible or is there any restriction in such an investment?

He will receive a fixed amount of rupees (15000) on his investment and if there will be any loss or damage of the car, the insurance company or myself will bear the financial loss on the car. What will be the Islamic ruling in this condition?

Bribery

Q: A police stopped a brother for speeding 91km in a 80km zone. So the brother asked him for a chance and told him that he just did some charity and if  the police could spare him. The police replied that since you just did some good deeds why not do a good deed for the police as well and give me something (money). Is that a bribe or a gift?

Attending khatams

Q: I was invited to attend a khatam. Can you explain what it is and am I in the wrong for not attending as I was requested but I follow the sunnah of Nabi (sallallahu alaihi wasallam) and was it ever mentioned to do khatam or milad and so on?