What is the sum of 90 minutes and 85 minutes?

90 mins + 50 mins = 140 mins 
60 mins ==1 hr  2*60 = 120 mins 
140 mins -120 mins= 20 mins
2 hrs ans 20 mins is the answer

To find the sum of two numbers you simply need to add them together. Therefore in this case:
90 + 85 = 175 minutes
This could also be expressed in hours and minutes as 1 hour is 60 minutes:
175/60 = 2 remainder 55 therefore it is 2 hours and 55 minutes.
Hope this helps!