Answer:
1- The amount of time passed in hours before getting a sunburn.
2- 30 minutes, 1 hour 30 minutes, 5 hours
3- SPF 15 so that person C won't get a sunburn until after 15 hours.
4- SPF 15 is more effective because when you add the time passed until you got a sunburn with SPF 4 and compared that to what you got when adding up the data from using SPF 15, you can see that it is more effective.
5- The number in the SPF rating stands for about how much time an average person can go without getting sunburned.
Hope this helps!
-Coconut;)
