Question

Write the following 24-hour clock into the 12-hour clock: \[23:42\].

Answer 1

Hint: Here, we will convert the 24-hour clock into 12-hour clock by adding 12 hours, subtracting 12 hours, and/or adding the letters AM or PM. 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.

Complete step by step answer:
A 24-hour clock starts at \[00:00\] and ends at \[23:59\].
A 12-hour clock starts at \[12:00\] AM and ends at \[11:59\] PM.
We can convert the 24-hour clock into a 12 hour-clock by adding 12 hours, subtracting 12 hours, and adding the letters AM or PM. In some cases, we do not even need to add or subtract 12 hours. Just adding AM or PM converts them into a 12-hour clock.
We add 12 hours to the 24-hour clock from \[00:00\] to \[00:59\] and add AM to convert them into a 12-hour clock.
By adding the letters AM, we can convert the 24-hour clock from \[1:00\] to \[11:59\], into a 12-hour clock.
By adding the letters PM, we can convert the 24-hour clock from \[12:00\] to \[13:59\], into a 12-hour clock.
We subtract 12 hours from the 24-hour clock from \[13:00\] to \[23:59\] and add PM to convert them into a 12-hour clock.
Now, the given 24-hour clock is \[23:42\].
This lies in the range \[13:00\] to \[23:59\].
We can convert the 24-hour clock \[23:42\] into a 12-hour clock by subtracting 12 hours and adding the letters PM.
Thus, we get \[23:42 - 12\] hours\[ = 11:42\] PM.


Note:
The 24-hour clock, popularly referred to in the United States and some other countries as military time, is the convention 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.