Final answer:
To cook mashed potatoes by yourself, it would take 30 minutes.
Step-by-step explanation:
To calculate the total time it would take to cook mashed potatoes, we need to analyze the given tasks and their prerequisites. Starting with Task 0, boiling water takes 10 minutes. Then, Task 1, peeling potatoes, takes 5 minutes. After that, Task 2, boiling potatoes, takes 3 minutes. Next, Task 3, mashing potatoes, takes 2 minutes. Finally, Task 4, chopping parsley, takes 10 minutes. Task 5, mixing butter and parsley with potatoes, requires the completion of Task 3 and Task 4. Since Task 3 takes 2 minutes and Task 4 takes 10 minutes, the minimum time required for Task 5 is 10 minutes. Adding up the time for all the tasks, the total time it would take to cook mashed potatoes is 10 + 5 + 3 + 2 + 10 = 30 minutes. Therefore, the correct answer is a. 30 minutes.