Nora read 4 books in 3 h 35 min. She took the same amount of time to read each of the first 3 books. She took 59 min longer to read the fourth book than each of the first 3 books. She finished reading all the books at 17 37. What time did she start reading the fourth book?
Duration that Nora took to read the first book = 1 u
Duration that Nora took to read the second book = 1 u
Duration that Nora took to read the third book = 1 u
Duration that Nora took to read the fourth book = 1 u + 59 min

Total duration that Nora took to read the four books 
= 1 u + 1 u + 1 u + 1 u + 59 min
= 4 u + 59 min

4 u + 59 min = 3 h 35 min
4 u = 215 min - 59 min
4 u = 156 min  

1 u = 156 min ÷ 4 = 39 min

Duration that Nora took to read the fourth book
= 39 min + 59 min
= 98 min
= 1 h 38 min

1 h 38 min before 17 37: 15 59

Time that Nora started to read the fourth book = 15 59

Answer(s): 15 59