Final answer:
The consumer's total expenditure is $29, and the total marginal utility is 78 utils. This is calculated by multiplying the number of movies and apps downloaded by their respective prices and marginal utilities.
Step-by-step explanation:
The question revolves around calculating the consumer's total expenditure and total marginal utility based on their weekly downloads. To determine total expenditure, we multiply the number of each item downloaded by its price and add these amounts together. For movies, the consumer downloads 4 movies at $5 each, resulting in $20. For apps, the consumer downloads 3 apps at $3 each, resulting in $9. The total expenditure is therefore $20 + $9 = $29. To calculate the total marginal utility, we multiply the marginal utility by the number of items downloaded. For movies, this is 4 movies × 12 marginal utility each, resulting in 48 utils. For apps, this is 3 apps × 10 marginal utility each, resulting in 30 utils. The total marginal utility is therefore 48 utils + 30 utils = 78 utils.