Modelling a billing problem

A tradesperson charges a fixed call-out fee of 40 euros, plus 25 euros per hour of work. 1) Write the function C(x) representing the total cost as a function of the number of hours, x. 2) Calculate the cost for a 3-hour job. 3) A customer has a budget of 190 euros: what is the maximum number of hours they can hire the tradesperson for?