At what time between 7 & 8 o'clock will the hands of a watch be in the straight line but no together
Explanation:
When the hands of the clock are in the same straight line but not together, they are 30 minute spaces apart.
At 7 o'clock, they are 25 min. spaces apart.
Minute hand will have to gain only 5 min. spaces.
55 min. spaces are gained in 60 min.
5 min spaces are gained in 
min = 
min
so, Required time = min past 7