The minute and hour hands of a clock are at right angles at 2 instances between 4 and 5pm. What is the time difference between the 2 instances? I answered this question with this formula: Angle = |30h - 11/2m| where I got m = 60/11. How to solve further? Please answer

Relative speed of both the hands is 11/2 or 5.5 degrees per minute For first time when they make 90 degrees minute hand has to travel 90degrees to coincide with hour hand and again travel 90 degrees again to make an the same angle so in total 90+90= 180 degrees Therefore 180/(Relative speed of both hands is 5.5degrees per minute)=180/5.5 =32.73 You can cross check as it makes 90degrees after 4 past 5.45 minutes and 4 past 38.18 minutes= i.e 38.18-5.45= 32.73 minutes

360/11 I guess this is SNAP 1st slot question