Question

Subtract the following $ 1{\rm{ minute }}15{\rm{ seconds}} $ from $ 4{\rm{ minutes }}25{\rm{ seconds}} $ .

Answer 1

Hint: In this problem we will first convert minutes to seconds. The idea to find a minute is one minute is equal to sixty seconds. Then subtract the seconds and convert the result to minutes.

Complete step-by-step answer:
The given time is $ 1{\rm{ minute }}15{\rm{ seconds}} $ and $ 4{\rm{ minutes }}25{\rm{ seconds}} $ .
The aim is to subtract one minute fifteen seconds from four minutes twenty seconds. First let us convert $ 1{\rm{ minute }}15{\rm{ seconds}} $ to seconds.
We know the formula to convert minute to seconds is given as,
 $ 1{\rm{ minute}} = 60{\rm{ seconds}} $
Now, let us convert $ 1{\rm{ minute }}15{\rm{ seconds}} $ into seconds, we obtain,
 $ \begin{array}{c}
1{\rm{ minute }}15{\rm{ seconds }} = 60{\rm{ seconds }} + 15{\rm{ seconds}}\\
 = 75{\rm{ seconds}}
\end{array} $
Similarly, we will convert the given time $ 4{\rm{ minutes }}25{\rm{ seconds}} $ into seconds, we get,
 $ \begin{array}{c}
{\rm{4 minute 2}}5{\rm{ seconds }} = 4 \times 60{\rm{ seconds }} + 25{\rm{ seconds}}\\
 = 240{\rm{ seconds}} + 25{\rm{ seconds}}\\
 = 265{\rm{ seconds}}
\end{array} $
Now, our aim is to subtract $ 75{\rm{ seconds}} $ from $ 265{\rm{ seconds}} $ , we get,
 $ 265{\rm{ seconds}} - 75{\rm{ seconds}} = {\rm{190 seconds}} $ .
Hence, now we need to convert $ 190{\rm{ seconds}} $ . To convert first we need to split $ 190 $ as, $ 190 = 60 \times 3 + 10 $
Hence, we know $ 190{\rm{ seconds}} = 60 \times 3{\rm{ seconds}} + 10{\rm{ seconds}} $ . Since, one minute is sixty seconds we get,
 $ 190{\rm{ seconds}} = 3{\rm{ minutes}}\;10\;{\rm{seconds}} $ .
Therefore, the result after subtraction is $ 3{\rm{ minutes }}10{\rm{ seconds}} $ .

Note: This problem can be done in another way that is just subtract seconds from seconds and minutes from minutes. But sometimes if the seconds obtained is negative then converting it will become difficult. Also, while converting seconds to minutes be careful.