Mrs Yap left home at 8 a.m. and drove towards the city. 1¹₃ hour later, Mr Yap left the house and drove at an average speed of 92 km/h towards the city. When Mr Yap reached his destination at 2 p.m., Mrs Yap was 14 km away from the city. Find Mrs Yap’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
¹₃ h = ¹₃ x 60 = 20 min
1¹₃ = 1 h 20 min

1 h 20 min after 8 a.m. = 9.20 a.m.

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

Time that Mr Yap took from 9.20 a.m. to 2 p.m. to reach his destination = 4 h 40 min

1 min = ¹₆₀ h
40 min = ⁴⁰₆₀ h = ²₃ h
4 h 40 min = 4²₃ h

Distance that Mr Yap drove
= 4²₃ x 92
= 429¹₃ km

Distance that Mrs Yap drove when Mr Yap reached
= 429¹₃ - 14 
= 415¹₃ km

Time that Mrs Yap took to travel from 8 a.m. to 2 p.m. = 6 h

Mrs Yap's average speed
= 415¹₃ ÷ 6
= 69²₉ km/h

Answer(s): 69²₉ km/h