We know that, 60 minutes = 1 hour
Now we borrow 1 hour from 48 hours in LHS,
5 hours 40 minutes = 5 hours + 40 minutes
= 4 hours + 1 hour + 30 minutes
= 4 hours + 60 minutes + 30 minutes
= 4 hours + 90 minutes
= 4 hours 90 minutes.
Therefore, the required value of A is 4.