Barbara read 4 books in 2 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 22 22. What time did she start reading the fourth book?
Duration that Barbara took to read the first book = 1 u
Duration that Barbara took to read the second book = 1 u
Duration that Barbara took to read the third book = 1 u
Duration that Barbara took to read the fourth book = 1 u + 59 min

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

4 u + 59 min = 2 h 35 min
4 u = 155 min - 59 min
4 u = 96 min  

1 u = 96 min ÷ 4 = 24 min

Duration that Barbara took to read the fourth book
= 24 min + 59 min
= 83 min
= 1 h 23 min

1 h 23 min before 22 22: 20 59

Time that Barbara started to read the fourth book = 20 59

Answer(s): 20 59