Betty read 4 books in 3 h 10 min. She took the same amount of time to read each of the first 3 books. She took 58 min longer to read the fourth book than each of the first 3 books. She finished reading all the books at 19 44. What time did she start reading the fourth book?
Duration that Betty took to read the first book = 1 u
Duration that Betty took to read the second book = 1 u
Duration that Betty took to read the third book = 1 u
Duration that Betty took to read the fourth book = 1 u + 58 min

Total duration that Betty took to read the four books 
= 1 u + 1 u + 1 u + 1 u + 58 min
= 4 u + 58 min

4 u + 58 min = 3 h 10 min
4 u = 190 min - 58 min
4 u = 132 min  

1 u = 132 min ÷ 4 = 33 min

Duration that Betty took to read the fourth book
= 33 min + 58 min
= 91 min
= 1 h 31 min

1 h 31 min before 19 44: 18 13

Time that Betty started to read the fourth book = 18 13

Answer(s): 18 13