Mrs Cheong left home at 7 a.m. and drove towards the city. 2¹₃ hour later, Mr Cheong left the house and drove at an average speed of 95 km/h towards the city. When Mr Cheong reached his destination at 1 p.m., Mrs Cheong was 11 km away from the city. Find Mrs Cheong’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
¹₃ h = ¹₃ x 60 = 20 min
2¹₃ = 2 h 20 min

2 h 20 min after 7 a.m. = 9.20 a.m.

Time that Mr Cheong left the house = 9.20 a.m.

Time that Mr Cheong took from 9.20 a.m. to 1 p.m. to reach his destination = 3 h 40 min

1 min = ¹₆₀ h
40 min = ⁴⁰₆₀ h = ²₃ h
3 h 40 min = 3²₃ h

Distance that Mr Cheong drove
= 3²₃ x 95
= 348¹₃ km

Distance that Mrs Cheong drove when Mr Cheong reached
= 348¹₃ - 11 
= 337¹₃ km

Time that Mrs Cheong took to travel from 7 a.m. to 1 p.m. = 6 h

Mrs Cheong's average speed
= 337¹₃ ÷ 6
= 56²₉ km/h

Answer(s): 56²₉ km/h