Final answer:
The 'extra 15 minutes' refers to the process of adding units of time, where 60 minutes is equivalent to one hour. When consolidating minutes, exceeding 60 should be converted into additional hours. For example, 1 hour 25 minutes + 20 minutes + 15 minutes equals 2 hours total.
Step-by-step explanation:
To understand where the 'extra 15 minutes' come from, let's review how to add units of time together. When adding time, it's important to convert 60 minutes into 1 hour as part of the process. Let's look at a few examples:
15 minutes + 60 minutes = 1 hour and 15 minutes, because 60 minutes is equal to 1 hour, so you have 1 hour + 15 minutes.
10 minutes + 20 minutes = 30 minutes, which is simply adding the two minute values together.
15 seconds + 45 seconds= 60 seconds, which is equivalent to 1 minute.
In a practical situation, if Maria planned errands before meeting a friend:
Maria estimates 15 minutes at the post office.
1 hour and 25 minutes at the mall.
20 minutes to drive to her friend's house.
If she leaves her house at 1:00 pm, the total time expected to be spent is:
1 hour 25 minutes + 20 minutes + 15 minutes = 1 hour 60 minutes, which when simplified becomes:
2 hours (since 60 minutes equals 1 hour).
Therefore, Maria will reach her friend's house at around 3:00 pm.
Now, regarding the 95th percentile for excess time used by customers or the quirky explanation by a friend for being late because of time perception differences at the top of tall buildings like the Empire State Building are interesting, though not directly related to the basic task of adding units of time.