Sabrina read 3 books in 2 h 59 min. She took the same amount of time to read each of the first 2 books. She took 59 min longer to read the third book than each of the first 2 books. She finished reading all the books at 17 16. What time did she start reading the third book?
Duration that Sabrina took to read the first book = 1 u
Duration that Sabrina took to read the second book = 1 u
Duration that Sabrina took to read the third book = 1 u + 59 min

Total duration that Sabrina took to read the three books 
= 1 u + 1 u + 1 u + 59 min
= 3 u + 59 min

3 u + 59 min = 2 h 59 min
3 u = 179 min - 59 min
3 u = 120 min  

1 u = 120 min ÷ 3 = 40 min

Duration that Sabrina took to read the third book
= 40 min + 59 min
= 99 min
= 1 h 39 min

1 h 39 min before 17 16: 15 37

Time that Sabrina started to read the third book = 15 37

Answer(s): 15 37