Answer:
22 hours 39 minutes
Explanation:
To simplify the expression, we must know the relationship between minutes and hours.
Since 60 minutes make 1 hour, then 99 minutes will be equivalent to
= 99/60
= 1.65 hours
= 1 hour 39 minutes
As such,
21 hours 99 minutes
= 21 hours + 1 hours 39 minutes
= 22 hours 39 minutes