Final answer:
Eleanor consumed a total of 2810 calories in a day and needs to burn off 810 extra calories. Aerobics burns 400 calories per hour, so she would need approximately 2 hours and 2 minutes of aerobics to burn the extra calories.
Step-by-step explanation:
The question involves calculating how many extra calories Eleanor consumed compared to her limit and how long she should exercise in aerobics class to burn off these extra calories. Eleanor had a total calorie intake of 1300 calories from breakfast and lunch combined, 655 calories from a slice of ice cream cake, and 855 calories from three pieces of pizza (3 x 285 calories per piece).
First, we calculate the total calorie intake for the day:
1300 calories (breakfast and lunch) + 655 calories (cake) + 855 calories (pizza) = 2810 calories.
By subtracting the maximum calorie intake limit Eleanor set for herself, we can find the excess calories:
2810 total calories - 2000 limit = 810 extra calories.
Knowing that aerobics burns 400 calories each hour, we calculate the time needed to burn the extra 810 calories:
810 extra calories / 400 calories per hour = 2.025 hours.
Since we typically don't measure exercise time in fractions of an hour, Eleanor would need to spend roughly 2 hours and 2 minutes doing aerobics to burn off the extra 810 calories.