The display of a 24-hour digital clock shows hours and minutes in the format XX:XX. For what fraction of a day is at least one 9 displayed on this clock?
+1639 link:::https://web2.0calc.com/questions/the-display-of-a-24-hour-digital-clock-shows-hours-and-minutes_1
There're three answers; 2nd and 3rd answers are correct!
+36916 the hours 09 and 19 both display a 9 for 60 minutes each
the other 22 hours have a 9 for 09 19 29 39 49 59 6 minutes per hour
24 hours = 1440 minutes
(60+ 60 + 6* 22) / 1440 = 252/1440 = 0.175 17.5 % of the time
