Question

A certain 12 - hour digital clock displays the hour and the minute of a day. Due to a defect in the clock whenever the digit 1 is supposed to be displayed it displays 7. What fraction of the day will the clock show the correct time ?
A. `1/2`
B. `5/8`
C. `3/4`
D. `5/6`

Answer 1

Correct Answer - A
The clock will show the incorrect time (between 1 - 2, 10 - 11, 11- 12, 12 - 1 day and night night both)
`:." in correct time "8 xx 60 = 480` (each minute it will display 1)
Remaining 20 hours it will show the incorrect time ` 16 xx 15 =240`
Total incorrect time = `240 + 480 =720`
correct time = 1 - incorrect time
` = 1-(720)/(24 xx 60)=1//2`