Q1. At what time between 7 and 9 o'clock will the hands of a clock be in a straight line but not together?
A 5 min past 7
B 5 5/11 min past 7 Correct
C 20 min past 7
D 7 3/10 min past 7
Explanation
At 7 o'clock, the hour hand is at 210 degrees and the minute hand is at 0 degrees, so the gap is 210 degrees. For the hands to be in a straight line but not together, the gap must be 180 degrees. The minute hand gains 5.5 degrees per minute over the hour hand, so it must close 30 degrees. Time needed is 30/5.5 = 60/11 = 5 5/11 minutes. Thus 5 minutes, 20 minutes, and 7 3/10 minutes past 7 do not give the required opposite alignment.