Need help quick quick quico

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers

F(x) = 1/x g(x)=x-4 can you evaluate (g*f)(0) ? why or why not?

Jonathan can type 20 documents in 40 minutes ,and susan can type it in 30 minutes and jack can type it in 24 minutes working together ,how much time will it is take them type the same document