1 hr = 60 min
1/6 hr = (60/6) min = 10 min
so the bell rings every 10 min. Since 1 hr = 60 min, this means that 2/3 of that is 40 min. So the bell will ring 4 times (divide 40 over 4) in the next 2/3 of an hour, which is the same as saying "the bell will ring 4 times in the next 40 minutes"
Answer: 4 times