1.  At what time between 5.30 and 6 will the hands of a clock be at right angles?
A. 43(5/11) min. past 5
B. 43(7/11) min. past 5
C. 40 min. past 5
D. 45 min. past 5

Answer: Option B

Explanation:

At 5 o'clock, the hands are 25 min. spaces apart.

To be at right angles and that too between 5.30 and 6, the minute hand has to gain (25 + 15) = 40 min. spaces.

55 min. spaces are gained in 60 min.

40 min. spaces are gained in :

60 x 40 min = 43 7 min.
55 11

∴ Required time = 43 7 min. past 5.
11