Three hours after Jilbert leaves, her little sister Harriet arrives and sees the new toy. Shrieking with excitement Harriet shouts 'faster, go on, faster'. The Wheelie Bot complies and starts going five times its original speed, zooming around the track again and again - poor Wheelie Bot :( When Jilbert got back and saw her poor Wheelie Bot exhausted she was not a happy Meerca!
The question is :
How many minutes in total did it take for the Wheelie Bot to run out of batteries??
(please round your answer down to the nearest minute)