Mrs Tan left home at 8 a.m. and drove towards the city. 1¹₄ hour later, Mr Tan left the house and drove at an average speed of 93 km/h towards the city. When Mr Tan reached his destination at 2 p.m., Mrs Tan was 13 km away from the city. Find Mrs Tan’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
¹₄ h = ¹₄ x 60 = 15 min
1¹₄ = 1 h 15 min

1 h 15 min after 8 a.m. = 9.15 a.m.

Time that Mr Tan left the house = 9.15 a.m.

Time that Mr Tan took from 9.15 a.m. to 2 p.m. to reach his destination = 4 h 45 min

1 min = ¹₆₀ h
45 min = ⁴⁵₆₀ h = ³₄ h
4 h 45 min = 4³₄ h

Distance that Mr Tan drove
= 4³₄ x 93
= 441³₄ km

Distance that Mrs Tan drove when Mr Tan reached
= 441³₄ - 13 
= 428³₄ km

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

Mrs Tan's average speed
= 428³₄ ÷ 6
= 71¹¹₂₄ km/h

Answer(s): 71¹¹₂₄ km/h