Answer:
I'm not sure about the function but here is the answer: 3
Step-by-step explanation:
Well, 75% of 1 is 0.75 + 75% of that + 75% of that and so on until you do it four times. Why four? Well it increases every 30 MINUTES so 30 min + 30 min + 30 min + 30min = 2 hours!
