Ella requires 3905 kJ of energy to do 2 hours of dancing a week, 1 hour of football a week, and 0.5 hours of swimming a week.
Ella, with a mass of 55 kg, does a series of activities in a week.
Let's calculate how much energy she needs for each activity in total.
Dancing
Ellas does 2 hours of dancing a week, which consumes 18 kJ/kg.h.
2 h × 55 kg × 18 kJ/kg.h = 1980 kJ
Football
Ella plays 1 hour of football a week, which consumes 25 kJ/kg.h.
1 h × 55 kg × 25 kJ/kg.h = 1375 kJ
Swimming
Ella goes swimming for 0.5 hours a week, which consumes 20 kJ/kg.h.
0.5 h × 55 kg × 20 kJ/kg.h = 550 kJ
Total energy expenditure
E = 1980 kJ + 1375 kJ + 550 kJ = 3905 kJ
Ella requires 3905 kJ of energy to do 2 hours of dancing a week, 1 hour of football a week, and 0.5 hours of swimming a week.
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