Answer :
Final answer:
Charles expended a total of 2500 kilocalories in one week, given his time spent and energy expenditure rates for swimming and walking.
Explanation:
The question asks how many total kilocalories Charles expended in one week, given that he swam for a total of 3.0 h and walked for a total of 9.0 h, with the corresponding energy expenditures being 340 kcal/h for swimming and 160 kcal/h for walking.
To answer this, we can simply multiply the time spent with each respective activity by its energy expenditure rate, and sum them to get the total weekly energy expenditure.
Therefore, for swimming, Charles burned 3.0 h x 340 kcal/h = 1020 kcal. For walking, he burned 9.0 h x 160 kcal/h = 1440 kcal.
Summing these values gives us a total of 1020 kcal + 1440 kcal = 2460 kcal for the week.
To two significant figures, this is represented as 2500 kcal.
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