A digital, 12-hour clock shows hours and minutes. During what fraction of the day will the clock show the digit 0 in its display? Express your answer as a common fraction.

Guest Jan 5, 2021

#1**+1 **

For each hour 100 200 300

there are 2 zeroes + 1 extra at 1000 = 25 zero minutes

each hour has a 10 20 30 40 50 after 12 x 5 = 60 more zero showing minutes

each hour has a 01 02 03 04 05 06 07 08 09 12 x 9 = 108 zero-minute hours

ALL of the munutes during 1000 hour have zero 54 more minutes (because the 10 20 30.... were already counted )

(25+60+108 + 54 ) / (12*60) = ............

Guest Jan 5, 2021

#1**+1 **

Best Answer

For each hour 100 200 300

there are 2 zeroes + 1 extra at 1000 = 25 zero minutes

each hour has a 10 20 30 40 50 after 12 x 5 = 60 more zero showing minutes

each hour has a 01 02 03 04 05 06 07 08 09 12 x 9 = 108 zero-minute hours

ALL of the munutes during 1000 hour have zero 54 more minutes (because the 10 20 30.... were already counted )

(25+60+108 + 54 ) / (12*60) = ............

Guest Jan 5, 2021