10 different names are put into a computer and one of the names is colin. on a saturday the computer chooses 2 names at random. the computer is set so that the same name can be chosen twice. what is the probability that colin is chosen at least once

Consider the function represented by the equation 1/2 j + 1/4 k equals 3 which shows the equation written in function notation with j as the independent variable

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?  

I'm confused on this could anyone me and show me what i need to do to solve it.