A group of 3 staff members maintain all the slot machines at Three-River casino. Each staff member can repair one slot machine every 6 hours on average with an exponential distribution. An average of 1 slot machine would fail every 4 hours, according to a Poisson distribution. The casino loses $25 revenue per hour for each slot machine that is not functioning. The casino pays each the three staff members an hourly wage of $15. What would be the total operating costs per hour if a fourth staff member is hired at the same cost? Round your answer to 2 digits after the decimal point