A toaster has 4 slots for bread. Once the toaster is warmed up, it takes 35 seconds to make 4 slices of toast, 70 seconds to make 8 slices, and 105 seconds to make 12 slices.

How long do you think it will take to make 20 slices?
If someone makes as many slices of toast as possible in 4 minutes and 40 seconds, how many slices do think they can make?