At what time between 10'O clock and 11'O clock the hands of the clock are right angle with each other.
1
8(10/11) past 10 and 37(2/11) past 10
2
5(5/11) past 10 and 38(2/11) past 10
3
8(2/11) past 10 and 39(5/11) past 10
4
7(10/11) past 10 and 37(2/11) past 10