Question

Add the following: 72 min 15 sec and 15 min 12 sec.

Answer 1

Hint: In this question, we will convert all the given time into seconds by multiplying the minute’s part by 60 and then adding them with the remaining seconds for that time. After that, we will take both the converted times and add them. The result obtained this way will be in seconds. Then convert it back in minutes.

Complete step-by-step solution:
We know that one minute is equal to 60 seconds.
Now convert 72 minutes in seconds,
$ \Rightarrow 72 \times 60 = 4320$
As the term is 72 min 15 sec. So, add 15 sec to it,
$ \Rightarrow 72\min 15\sec = 4320 + 15$
Add the term on the right side,
$ \Rightarrow 72\min 15\sec = 4335\sec $
Now convert 15 minutes in seconds,
$ \Rightarrow 15 \times 60 = 900$
As the term is 15 min 12 sec. So, add 12 sec to it,
$ \Rightarrow 15\min 12\sec = 900 + 12$
Add the term on the right side,
$ \Rightarrow 15\min 12\sec = 912\sec $
We will now add both these values as follows,
$ \Rightarrow 72\min 15\sec + 15\min 12\sec = 4335 + 912$
Add the term on the right side,
$ \Rightarrow 72\min 15\sec + 15\min 12\sec = 5247\sec $
We have to now write 5247 seconds as a multiple of 60 to convert it back to minutes and seconds’ form. Divide the term by 60,
$\begin{array}{l}
\left. {60} \right)5247\left( {87} \right.\\
\,\,\,\,\,\,\,\underline {480} \\
\,\,\,\,\,\,\,\,\,\,447\\
\,\,\,\,\,\,\,\,\,\,\underline {420} \\
\,\,\,\,\,\,\,\,\,\,\,\,\,27
\end{array}$
So, the quotient part is the minute and the remainder is the second.
$ \Rightarrow 72\min 15\sec + 15\min 12\sec = 87\min 27\sec $

Hence, the sum of 72 min 15 sec and 15 min 12 sec is 87 min 27 sec.

Note: Remember that in such types of questions, we have to convert all different units of time into any convenient unit and then perform the required operations on them. To convert hours to minutes or minutes to seconds, we simply multiply by 60, and to convert seconds to minutes or minutes to hours, we divide by 60.