Jade read 3 books in 2 h 38 min. She took the same amount of time to read each of the first 2 books. She took 50 min longer to read the third book than each of the first 2 books. She finished reading all the books at 22 36. What time did she start reading the third book?
Duration that Jade took to read the first book = 1 u
Duration that Jade took to read the second book = 1 u
Duration that Jade took to read the third book = 1 u + 50 min

Total duration that Jade took to read the three books 
= 1 u + 1 u + 1 u + 50 min
= 3 u + 50 min

3 u + 50 min = 2 h 38 min
3 u = 158 min - 50 min
3 u = 108 min  

1 u = 108 min ÷ 3 = 36 min

Duration that Jade took to read the third book
= 36 min + 50 min
= 86 min
= 1 h 26 min

1 h 26 min before 22 36: 21 10

Time that Jade started to read the third book = 21 10

Answer(s): 21 10