Mathematics: Security Guards and Stolen Radios

problem: Twenty-first Century Electronics has discovered a theft problem at its warehouse and has decided to hire security guards. The firm wants to hire the optimal number of security guards. The following table shows how the number of security guards affects the number of guards affects the number of radios stolen per week.

Number of security guard Number of radios stolen per week
0 50
1 30
2 20
3 14
4 8
5 6

problems:

1) If each security guard is paid $200 a week at the cost of a stolen radio is $25, how many security guards should the firm hire?

2) If the cost of a stolen radio is $25, what is the most a firm is willing to pay to hire the first security guard?

3) If each security guard is paid $200 a week and the cost of a stolen radio is $50, how many security guards should the firm hire?