Hint: Here, we will subtract the 3 days 12 hour from 5 days 20 hours. We know that, One day = 24 hours. After that, we need to convert the given data into simpler form and then subtract and thus we will obtain the answer.
Complete step by step answer:
A 24-hour clock starts at 00:00 and ends at 23:59 whereas, a 12-hour clock starts at 12:00 AM and ends at 11:59 PM.
We know that, to convert days and hours into hours, One day = 24 hours.
Hence, we need to convert both the 3 days 12 hours and 5 days 20 hours into hours.
Let us convert, 3 days 12 hours \[=\left[ \left( 3\times 24 \right)+12 \right]\]
Here, we are added 3 times the 24 and then added 12.
Hence, 3 days 12 hours is equals to 84 hours.
Now convert 5 days 20 hours into hours.
5 days 20 hours\[=\left[ \left( 5\times 24 \right)+20 \right]\]
Here, we are added 5 times the 24 and then added 20.
Hence, 5 days 20 hours is equals to 140 hours.
Now, let us subtract 3 days 12 hours from 5 days 20 hours,
\[\Rightarrow 140-84=56\] hours.
56 hours can be written as \[48+8\]hours,
The above can be simplified as,
\[\left[ \left( 2\times 24 \right)+8 \right]\]hours,
In words, 2 days and 8 hours.
Therefore, 2 days and 8 hours is the correct answer.
Note: The 24-hour clock, popularly, referred to in the United States and some other countries as military time, is the convection of time keeping in which the day runs from midnight to midnight and is divided into 24 hours. This is indicated by the hours passed since midnight, from 0 to 23.