Final answer:
Bobby will take approximately 44 days to lose 10 kg by eating a well-balanced diet and exercising daily.
Step-by-step explanation:
To calculate how long it will take Bobby to lose 10 kg, we need to convert the weight he expects to lose per day from ounces to kilograms. Since there are approximately 35,273.96 ounces in 1 kilogram, we can calculate that Bobby expects to lose 8 oz/day * (1 kg/35,273.96 oz) = 0.000226767 kg/day.
Now, we can divide the total weight he wants to lose, 10 kg, by the amount he expects to lose per day: 10 kg / 0.000226767 kg/day = 44,073.6237 days. Therefore, it will take Bobby approximately 44,073.6237 days to lose 10 kg.
Since the options given are in whole numbers, we can round the result to the nearest whole number. The closest option is D, 44 days.