Answer: Trail mix and shower sponges can be predicted for the cost of 100 items.
Step-by-step explanation: this is because those charts have a constant rate of change. For the trail mix chart, for every pount of trail mix the cost is $3.00 this doesn't change. The same method works for the shower sponge chart. The other two charts vary in price so you couldn't predict the cost of 100 units.