Which of the following individuals experiences the highest calorie cost?

A. Sara, who weighs 145 lbs., and does step aerobics (0.062 cal/lb./min) for 35 minutes.

B. Ben, who weighs 180 lbs., and walks on the treadmill (0.048 cal/lb./min) for 25 minutes.

C. Mary, who weighs 120 lbs., and rides her bike (0.076 cal/lb./min) for 20 minutes.

D. Andrew, who weighs 163 lbs., and swims (0.058 cal/lb./min) for 30 minutes.

E. Kia, who weighs 185 lbs., and runs on the treadmill (0.061 cal/lb./min) for 25 minutes.

To solve the problem of determining which individual experiences the highest calorie cost, we can follow a series of steps for each person. We will calculate the number of calories burned based on their weight, the type of activity they're doing, the rate at which calories are burned per minute for their weight, and the duration of the activity.

Let's break it down for each individual:

1. Sara:
- Weight: 145 lbs.
- Activity: Step aerobics
- Caloric burn rate: 0.062 calories per pound per minute
- Duration: 35 minutes

Calculation:
[tex]\[
\text{Calories burned} = 145 \times 0.062 \times 35 = 314.65 \text{ calories}
\][/tex]

2. Ben:
- Weight: 180 lbs.
- Activity: Walking on the treadmill
- Caloric burn rate: 0.048 calories per pound per minute
- Duration: 25 minutes

Calculation:
[tex]\[
\text{Calories burned} = 180 \times 0.048 \times 25 = 216 \text{ calories}
\][/tex]

3. Mary:
- Weight: 120 lbs.
- Activity: Biking
- Caloric burn rate: 0.076 calories per pound per minute
- Duration: 20 minutes

Calculation:
[tex]\[
\text{Calories burned} = 120 \times 0.076 \times 20 = 182.4 \text{ calories}
\][/tex]

4. Andrew:
- Weight: 163 lbs.
- Activity: Swimming
- Caloric burn rate: 0.058 calories per pound per minute
- Duration: 30 minutes

Calculation:
[tex]\[
\text{Calories burned} = 163 \times 0.058 \times 30 = 283.62 \text{ calories}
\][/tex]

5. Kia:
- Weight: 185 lbs.
- Activity: Running on the treadmill
- Caloric burn rate: 0.061 calories per pound per minute
- Duration: 25 minutes

Calculation:
[tex]\[
\text{Calories burned} = 185 \times 0.061 \times 25 = 282.125 \text{ calories}
\][/tex]

Now, let's compare the total calories burned by each individual:

- Sara: 314.65 calories
- Ben: 216 calories
- Mary: 182.4 calories
- Andrew: 283.62 calories
- Kia: 282.125 calories

After reviewing these calculations, we see that Sara experiences the highest calorie cost, burning a total of 314.65 calories.