Question

It takes Ronnie $43$ minutes $34$ seconds to do his workout. If he wants to finish his work out by $01:22:20$ PM when should he start?

• A. $12:46:38$ PM
• B. $12:38:46$ PM
• C. $12:36:48$ PM

Answer 1

The correct option is B $12:38:46$ PM

End time of workout $=01:22:20$ PM
Time taken for the workout $=43$ minutes $34$ seconds.

So, to find out the time when he should begin his workout, we have to subtract the time taken from the finish time.

For convinience, we will convert the end time to the military format:



Then we will do the subtraction as follows:
Here, start time would be also in Military format.

To make subtraction possible, we need to borrow one hour i.e. 60 minutes from $13$ hours hence making it $12$ hours and will add those 60 minutes with 22 minutes
$\Rightarrow 60+22=82$ minutes


Still there are $20$ seconds which is less than $34$ seconds, so we need to borrow 1 minutes i.e. 60 seconds from $82$ minutes, hence converting it into $81$ minutes and will add those 60 seconds with 20 seconds.

$\Rightarrow 60+20=80$ seconds.
Then we do the subtraction as follows:


So, Ronnie must start his working out by $12:38:46$ PM.