Math - Dan rented two movies to watch last night. The first was 1 hour 40 minutes

Dan rented two movies to watch last night. The first was 1 hour 40 minutes long, the second 1 hour 50 minutes long. How much time did it take for Dan to watch the two videos? 

a. 4.5 hours 

b. 3.5 hours 

c. 2.5 hours 

d. 1.5 hours

Answer: b. 3.5 hours 

Change the hours to minutes: 1 hour 40 minutes = 100 minutes; 1 hour 50 minutes = 110 minutes. Now add: 100 minutes + 110 minutes = 210 minutes. Now change back to hours and minutes: 210 minutes ÷ 60 = 3.5 hours.