a laptop charges up by 15 % every 20 minutes. How much charged will be after two hours?
In every hour, there are 3 sets of 15 minute blocks. So in 2 hrs, there are 8 sets. What is 8x15%?
In each hour, there are 3 sets of 20 minutes. 2 hours has 6 20 minute sets.
6x15% = ?