Mrs Loo left home at 9 a.m. and drove towards the city. 2¹₄ hour later, Mr Loo left the house and drove at an average speed of 99 km/h towards the city. When Mr Loo reached his destination at 3 p.m., Mrs Loo was 11 km away from the city. Find Mrs Loo’s average speed in km/h. Express your answer in mixed number.
1 h = 60 min 
¹₄ h = ¹₄ x 60 = 15 min
2¹₄ = 2 h 15 min

2 h 15 min after 9 a.m. = 11.15 a.m.

Time that Mr Loo left the house = 11.15 a.m.

Time that Mr Loo took from 11.15 a.m. to 3 p.m. to reach his destination = 3 h 45 min

1 min = ¹₆₀ h
45 min = ⁴⁵₆₀ h = ³₄ h
3 h 45 min = 3³₄ h

Distance that Mr Loo drove
= 3³₄ x 99
= 371¹₄ km

Distance that Mrs Loo drove when Mr Loo reached
= 371¹₄ - 11 
= 360¹₄ km

Time that Mrs Loo took to travel from 9 a.m. to 3 p.m. = 6 h

Mrs Loo's average speed
= 360¹₄ ÷ 6
= 60¹₂₄ km/h

Answer(s): 60¹₂₄ km/h