To find the number of calories Davis burns while running for 30 minutes, we can use the information that he burns 1080 calories running for 2.5 hours.
We know that 30 minutes is 1/120 of 2.5 hours. So, we can divide the total number of calories by 120 and we get the calorie burn for 30 minutes:
1080 calories / 120 = 9 calories
The number of calories Davis burns while swimming for 30 minutes can be determined by using the equation y = 266x, where x represents the number of hours he swims. We know that he swims for 30 minutes, or 1/120 hours, so we can plug that value into the equation:
y = 266(1/120) = 2.216 calories
So, Davis burns 7 calories more running for 30 minutes than swimming for 30 minutes, assuming the rates remain constant.