The average adult human burns 2.00x20^3 kcal per day in energy. What is this rate in kJ per hour?

1.61 × 10⁶ kJ

Explanation:

The human burns energy so as to be healthy.

The amount of energy burnt per day by an adult human is 2 × 20³ kcal per day. Since there is 24 hours in a day, the amount of energy burnt per hour is 2 × 20³ × 24 = 48 × 20³ kcal per hour.

The conversion rate of kcal to kJ is 1 kcal = 4.184 kJ. Therefore converting the kcal per hour to kJ per hour gives:

48 × 20³ × 4.184 = 200.882 × 20³ kJ = 1.61 × 10⁶ kJ