Option C) 5 hours
The log boat covers 5 km in an hour
To cover every 5 km, the log boat takes1 an hour.
As we know,
25 km = 5 km +5 km +5 km +5 km +5 km
Time taken by the log boat = 1 hr + 1 hr + 1 hr + 1 hr + 1hr
= 5 hr
So, the time taken by the log boat to cover 25 km in 5 hours